I am also 23, never had a relationship or even a date, and find it very difficult to have feelings for anyone, and I have low self esteem, and I don't expect anyone to care for or about me, and I find the thought of me being in a relationship or having feelings for someone repulsive. Even thinking of the most repulsive person I know being in a relationship doesn't make my skin crawl as much as thinking of myself doing those things.
Unlike you though deep down inside I do secretly wish I could be with someone, but I have accepted that I won't be.

I know some of the reasons I feel the way I do though, perhaps they might be similar. I grew up in a family of abusive relationships, all I've seen is the negative, because it's been programmed so much into my head that I really pick up on the flaws of relationships. Then there is the fact my mother was VERY open about sex, talking about it in detail, watching sex shows on TV (real sex not simulated), leaving the door open when she had sex, talking about the people she had or wanted to sleep with. So now sex revolts me because I just think about her all the time when I think of sex.
So I grew up with a fear of intimacy and sex. Now, I'm so used to feeling that way, and I've so many times avoided having feelings for someone, talking myself out of anything I may have felt for anyone, being defensive and protective of myself, that it has really altered my thought process. I don't even know which feelings are FEELINGS, or envy.
Have you over the years done the same thing? Talked yourself out of any feelings, or convinced yourself nobody likes you, or have you experienced any negative relationships that have affected your view on relationships?