Marriage or not

I'm getting married in September and right now I don't see that even happening. My fh and I been fighting a lot lately and I keep telling myself I don't even know if I still even want to marry him. Ever since we've gotten in engaged our relationship has changed and we just hardly don't get along which its crazy because before we hardly never argue. I feel like he and I want two different things plus he's checked out on being involved in our wedding and I've totally stopped planning our wedding because I feel so alone in this and I just am over it. I've been married before and I just don't want another failed marriage so now that I'm feeling alone in this relationship it's like I've checked out on this whole wedding stuff.

This should be a happy time and it's not at all.. I'm scared that my relationship is going to be over by the time we're supposed to be getting married..