I have no idea why I don't feel the way others do!

I feel like no matter who I am with in a relationship, I get sick of them. It's very weird. I just get annoyed with what their saying almost all of the time. The thing is, my eyes are never driven towards anyone else. It's not like I see other men and I'm craving to be with other men. It's more about an annoying nagging feeling that I just want to be alone or be around friends. I have no idea why I am this way. The ONLY time I haven't gotten sick of someone is a guy I was with for four years, BUT I didn't see him as more than a friend. I wasn't interested in kissing, hugging, sleeping together anymore. That's why I broke it off. I just didn't care. I saw him as a friend and friend only. It's like I can't replenish those feelings after the honey moon phase is over. Most of these men aren't even bad. I feel like it's me. I get so bored. And tired. Other women express that they "never get tired" of being around their SO and this is just a weird concept to me because I never felt like that, ever. I'm mid 20s and have had several relationships.