Lonely but fine alone

I'm so lonely but also good alone. It's so confusing. I see other people in relationships and reminisce about when I was in one and sometimes I miss it. I miss the physical affection, I miss the sexual tension and spending time with someone I love. But over time, you start getting used to them and it's not as intense as it was before. I'm worried if I do get in a relationship, especially a healthy one, I'll end up getting too used to them and crave something else. Of course I wouldn't want to hurt the person I'm with so I think of that. I also think that I'm better off alone because I don't wanna be liked by someone only because the people they were originally interested wasn't interested in them or they felt as though the person they like is out of their league. I want a guy that sees me in a room full of girls and picks me first because he likes me. I don't wanna feel like an afterthought and most of the time I feel like I'm not that appealing anyways so who really would want me? I want affection so much yet I feel like it's unobtainable for me.