I'll tell you a story from personal experience. I am a nice person too. I try to treat my girlfriends with respect and manners. I noticed the same thing that you are now figuring out, many years ago. I thought that having a girlfriend would make me happier, so a couple years ago, I tried to become a douche bag. I did get a girl to be interested in me. When she called, I would sometimes just ignore the phone, even though I knew that she knew I was home. I would make insensitive jokes to her about her hobbies and career (how little money she made etc.). I would even tell her how annoying she was being, calling me all the time (and I really loved it when she would call me). The truth is, I admired her for the career she was in. She was a teacher, and I don't know of a more noble profession. However, she was happy that she was with me.
You know what I did though. I finally told her after several months that I was tired of being something I'm not, just so she would like me more. I told her that I thought she was doing wonderful things with her life, and I just couldn't be fake anymore. I knew that would break the relationship, so I broke up with her that day and decided not to ever go back to being that guy again.
See, I didn't want to be a jerk, but I felt forced to by societal pressure. The truth is though, I'm a happier man, now that I am just my nice old self. If I never find a girlfriend, that would be better than turning into what I hate. We need to stand up for our rights to be nice, and be acknowledged.
Women, just because we're nice, doesn't mean that you have the right to treat us like crap. I know that most of you hate nice guys, but that's really your own problem. Get over it! We're nice, and we're not changing, just to appease you.