Wow, lots of good responses to this, thanks guys, and I'm glad to see that I'm not the only one here with this dilemma. I'll try to address the responses as much as I can.
First off, I remember that my first real serious relationship was in high school senior year. Before that, I almost didn't really have enough time for girls, because I played sports pretty seriously. Anyways, this girl was with me for a year, and there weren't too many complications, and I was the one who eventually broke it off because she just didn't do it for me. After that, I've had nothing but short-term relationships.
Recently, I've been more inclined to enjoy the stability that comes from a more steady relationship, but even then, I'm looking at maybe 1 month tops, even with girls who I feel are very compatible.
Interesting view on LTR, AVSguy01. I remember back in the day, before this board, the whole concept of being a challenge was not even an idea I remotely knew about. I wasn't really a challenge, it's just that I wasn't into girls enough for me to want to be around them all the time. I actually was more into sports than women, so I guess inadvertently I was a challenge in that sense.
Oxide, my last relationship I didn't even make a move on the girl until she was practically begging to kiss me. Then I kissed her, and she was all over me from that point. There was no way I was going to be able to hold out on the physical stuff because she initiated it most of the time. However, I think what happened is that that just opens Pandora's box and it's like a drug, and once you get some from her, you want to do it all the time. It's a vicious cycle. Anyways, I think that part of it is certainly the fact that I become some more sexually driven and it seems like all we'll do is make out and get physical with each other when we're together. However, we try to talk, but eventually it leads to the physical stuff. I have no idea what to do about it, but apparently if it doesn't stop, I'm going to be a bachelor for life who just goes around having flings. Like I said, it gets old after a while.