How come the women I like just want to be friends but the women who want me I don't like for dating and a relationship?

Hi all. This happens to me quite a bit. I think I'm a nice guy and have a lot to offer that special woman. Sometimes I'll have sex with women while hoping they'll date me afterwards but then they lost interest and tell me they just want to be friends. I don't know what it is. I'm not financially rich but I got a Bachelors degree, work full-time and am physically fit. I'm over 35, never been married and have no kids. People tell me I'll find "the one" but I've been hearing that for over 20 years and it still hasn't happened. What do you think the problem is? Any answers would be nice. Thanks.