Yeah bro, that's totally normal. I'd say don't get too hung up on it - but you will anyway ;)
Part of us always wants our ex's to sit in a little box for the rest of their lives so they don't meet anyone else (it's selfish but true). But the reality is they (and you) will move on to other people. Some things about that other person they might like more or less... or it might be completely different. You'll never know-- and probably shouldn't know as you are moving along with your life too and don't need hangups like that getting in the way or your personal productivity.
Just remember that we're all going through or have gone through this kind of thing. You're not alone.
Just hang in there and try to focus on yourself. Become bigger and stronger.