I feel the same way. I have met people that I have liked to hang out with/date, but I like having my alone time too.
I don't know how they can stand being around each other so much and then get disappointed when they can't see each other very often. Coworkers or friends of mine in serious relationships/marriages always say " I haven't been able to spend time with my husband/boyfriend all week, ugh I miss him so much!" I just don't get it. How can you be around someone that much and not die of boredom?
I think there are enough people in the world that you can find someone who agrees with how you feel about this. Like maybe a casual girlfriend/an open relationship. I would like something that was still serious but not serious at the same time. Like if I wanted to go do my own thing, I could, without it causing any problems. If they found a girl they though was cute, they could take her out, not problems. But like, we were still "together." That probably doesn't make any sense, but if something like that were possible, it would be nice.