*Update in comments* NWR: best friend in love with an engaged man

I lived once together with 3 room mates. One of them did exactly the same as your friend and we were concerned for her and the girl he was engaged to. When he would come over we always played love songs that expressed our feeling to him and he did not want to come over any more. One day my friend told him that she saw him on the beach with his fiance and how pretty she was (she did not see him and had no idea how she looked). He got nervous and stopped seeing our friend. We were 20 and probably this was not the way to act ... nowadays I agree fully with MrsBdeG.

My thoughts are that his FS should know. I know it's none of anyone's business and what not, but if you were that FS I'm sure you'd want to know before you make a terrible mistake in marrying such a pig.

@mrsbdeg for the win!! Everything you said is 100% perfect.

@op, I am truly sorry you have to deal with this. But it seems like you are trying to solve this issue in a very mature and respectful way. I wish you the best and please keep us updated!

@MrsBdeG I love the pettiness.

Maybe having an honest conversation with her... Even if he and his FS split up and he dates your sister, he won't change. Best saying I've ever heard, "he who cheats with you, will cheat on you." Either way this ends, she will most likely have a broken heart, and as her sister, you don't want to see her hurt.

Once a cheater, always a cheater.

I would definitely shut down them being in your apartment together ASAP.

That really sucks, though. But there's not much you can do...

Your apartment, so you have a say on who comes over. Regardless if her name is on the lease or not. When the FS comes and kicks in the door you both will be responsible. IJS

Since @MrsB pretty much hit the nail on the head on most points I will just say this.

What your friend and this guy are doing is horrible and wrong. But, despite the bad decision she has made she is still your friend and roommate. She could very well be racked with guilt over this, and is probably blinding herself from the reality with willful/wishful thinking. I think you need to sit down with her and let her know that while you do not condone her actions and you do not support her relationship you are still there for her. Maybe being able to talk to someone about the situation will help her realize that its a fallacy. Overall, you will not be able to talk her out of it, but if you begin to push her out of your life or make her feel like she has no one else to turn to she may only fall down deeper down the rabbit hole with this guy.

I agree that since it is her space as well you cannot outright ban him. However, you can sit down with her and let her know you do not support the relationship, and his presence makes you feel uncomfortable and request she not bring him around when you are there or limit activity in common spaces.

I don't know your friend and her boy toy but I dislike them both SO MUCH.

I dislike him, because he is a LIAR and he is disgraceful and I dislike her, because she is immoral/has no respect for herself for getting involved with a man who is about to get married to ANOTHER WOMAN... I hope she finds out and ends it with this a-hole.

Ask your friend this question: HOW WOULD "YOU" FEEL IF YOU ARE ENGAGED TO A MAN AND HE DOES THIS BEHIND YOUR BACK?

EXACTLY.

@MrsBdeG hit the nail right on the head. And OP, normally I would agree that a friend's relationship isn't your business, but she's made it your business by bringing it into your home. It's unfair of her to put you into this position as well. It's probably a difficult approach to take, but when you talk to her, try to come from a place with as little judgement as possible, because I'm sure she knows the relationship is wrong and she's likely to come from a defensive place, especially if she feels like she's being judged.

The roommate/best friend made it her business, FFS.

OP, I'd want nothing to do with that situation and I'm really sorry you now know too much. But I wouldn't allow him over, or I'd do my best to keep him from coming over. He's a taken man, and I wouldn't want it on my conscience that an almost-married man is sleeping with my friend in our apartment. Tell her that it's really inappropriate and she needs to think of this relationships long term options, which is probably a non-existent relationship. She needs to end things before she gets seriously hurt, and that's the approach I'd take.

This is going to end horribly when he marries his fiance and cuts your friend off without notice. And rest assured that is exactly what is going to happen.

You can give your opinion/advice and tell her how you feel. I'd do this one time as a friend and be done with it - because really you expect grown women to know this already.... After you have said your piece, I wouldn't discuss this with her again or engage in any conversation about him with her. I would not ban him from your home as others have suggested. Nor would I contact his fiance. Neither are your place to do. She pays rent there as well and technically he's not exactly married.

Gross. I wouldn't be able to look at him without cringing. He wouldn't want to come back to my apartment, I am the WORST at hiding my feelings. lol.

@mrsbdeg on point as always.

This nearly exact thing happened to me. My roommate (and closest friend) started "seeing" a married man. He lived out of state so it was a long distance affair which made me even more confused by it, but it persisted for several YEARS.

It ended up ruining our friendship, to be honest. Because he was long distance, I was able to ignore it to a certain extent, but I made sure she knew how I felt about it. And I did tell her he wasn't allowed in my house on any terms, which maybe in the end wasn't the right way to act, but I couldn't stomach a married man cheating on his wife in my HOME.

Then, when I started seeing FH she got super bitter and resentful toward me. I realized she wanted me to be miserable with her rather than have a happy, meaningful relationship with someone else. I moved out about 5 months into my relationship with FH because she was SO AWFUL to him when he was over. She's not invited to the wedding because of her horrible treatment of us as a couple, though all of our mutual friends are. I feel like she should be there, oddly, though I know I made the right decision.

I should say, though, that we've recently gotten more and more friendly toward each other. There's no animosity between us, and we can have civil conversations about common interests. Though, I know we will never be as close as we once were...

All of that is to say... definitely follow @MrsBdeG's advice because it's way better than how I behaved in the same situation. Also, don't be surprised if your friendship suffers for a little bit. My friend wasn't really a great friend all around, so cutting her out made sense in a lot of ways. If your friend is worth her salt in every other way but this, it's probably salvageable in the long run, even if it gets bumpy for a little while.

Not your business. But my cousin (who's a best friend to me) was with a married man (20 years her senior) Long story short they eventually moved in together and she worked for him. It was a 5 year relationship and she finally ended it in September. I had my opinions but didn't share them unless asked by her. I wanted to stay neutral with her in case she needed to come

To me about anything, she didn't feel judged.

Ugh. What a tough situation. I would feel very uncomfortable. I'm afraid I would have to say something to my friend. I would definitely point out that she's hurting someone. I might even find her pictures on social media to look through so she could see how happy they appear together and the lie he is telling to her.

I'm VERY straightforward and I would tell her like it is: " don't do something you don't want to be done to you" I would also tell her she is being a bish........ Sorry, but not sorry.I am comfortable with all my friends to be brutally honest.

So I know some PP had asked for an update on this whole debacle. I unfortunately have been unable to talk about this with my friend face to face still. She keeps saying we will but just isn't ready. As of today however, she did text me and tell me that the guy has left his fiancé. The fiancé has left their shared apartment and broken the lease so now my best friend and him are trying to "figure things out". What that means I do not know, I am just hoping it does not affect our current living situation. Thanks again though for all the advice you guys gave, and I have used some of it in the few text messages I have sent her despite her not wanting to hear it.

Why would she want a guy who would do that?