DJ, AO, SD? I don't know what these mean?

So things have been pretty good. I'm in my marriage for me. I feel like I'm taking care of my part.

One thing I'm scared of though, and I'm not sure if it matters or not. I feel like I settled.. not for the person he is.. but for how I felt about him. I think I thought he was a good choice, but deep down if I was honest, it's not really what I wanted... and maybe still what I don't want. How do I reconcile those feelings?
I feel like I'm ready to be committed on my side, but not without compromising how I feel. I don't think I really 'loved' him when we got married.. and I'm still afraid eventually it will get the best of our relationship, and I'll fall for someone else, even if I never act on it, and always stay in the relationship.

Maybe I'm setting myself up to be resentful again? like, 'sure I'll stay, but I know I'll just fall for someone else, but I'll stay faithful, and just resent him and our marriage'.

any thoughts about how you should feel about your spouse when you marry them? I'm willing to commit, but part of me is afraid that I can't engage myself emotionally in my marriage... is it possible that you just can't feel a certain way about someone? What is the importance of feelings? Is commitment enough?