Small Bridal Party?

You do not need to have even sides. DH had 5 friends on his side (although one officiated) and I had 4 on my side (one of my best friends was deployed and couldn't come to the wedding) and my "maid" of honor was actually my brother, so it was 7 men in suits and 3 women in dresses. None of my photographs look weird because I hired an amazing photographer (but any competent photographer can make it not look awkward with spacing).

I have 4 women in my life who have major real estate in my heart, and my brother, of course, is another person I couldn't imagine NOT having by my side. When one of my bridesmaids couldn't come because of her deployment, I didn't replace her because I had already elected my nearest and dearest. That should be what dictates your bridal party rather than numbers. Same for your husband-elect (my new favorite phrase). If my husband had been someone else, it wouldn't have affected who I had on my own side, do you see what I mean?

DH had 5 people, I had 4.

You do not HAVE to have a bridesmaid if you don't want one. You can skip, or have a bridesman, or have as many as you want. It's entirely up to you.

Like everyone has said, you don't need to (and shouldn't, for a variety of reasons) have matching sides. There's literally nothing wrong with your future spouse having a best man and you not having an attendant. And on the flip side, if you do really want bridesmaids, there's no reason your future spouse would have to add more attendants that he doesn't want.

And finally, you can absolutely invite your friends to get ready with you without them being bridesmaids. I think you have some "rules" stuck in your head that aren't real rules. Let them go and make your decisions based on what you really want.