The downside to casual relationships

I should start off by stating that I realize I have a pretty fucking amazing life.
Besides the fact that just being american puts me near the top of the pile, standard of living-wise, I have very, very little to bitch about. I have a great job that pays frankly an absurd amount of money for the work I do. I have great family and friends. I'm tall, handsome, and fit enough to attract plenty of ladies. I really do have it made. So don't think for a minute that i'm complaining, cause i'm not. This is mostly just an observation.

I date a lot of women, and have sex with most of them (and even a few I don't date) but for the last couple years, every single one of those relationships has been "casual". The closest I have been to a serious relationship is introducing Dirty to my parents, and that was only because we were vacationing in the same hotel.

However, I am always open and honest with every woman about what i'm interested in. They all know from the beginning that I am not gonna settle down and be anyone's boyfriend. Hell, I never even hint I am interested in being exclusive. I'm interested in easy, fun, drama-free flings. Obviously, plenty of women aren't interested in such a 'relationship', but I haven't had much trouble finding plenty of women who are...or who are for a while...

Every good thing comes to an end, and for me, they end one of three ways:

1) dumped for the new boyfriend
This is the easiest for me. I completely understand that i'm often her stand-by, to be dropped once something better comes along. I am perfectly ok with this. The beauty of a no-commitement fling is the no-commitment. Luckily, it usually ends with well-wishes for her new relationship and thanks for the great times.

2) dumped for the prospect of a boyfriend
Though this is understandable in theory, in practice, it doesn't make sense to me. I understand wanting a boyfriend, and I understand needing to be available to find one. But, hooking up with me on a semi-regular basis is not going to prevent you from meeting your next boyfriend...Unless you tell every guy you go out with you are hooking up with another guy on a semi-regular basis.

3) dumped because she wants more, or having to do the dumping.
Honestly, this one sucks. Unrequited feelings can be really hard to get over. I know this from experience and try to prevent this situation be being honest and open. It does not work. Some women hear me say, "I don't want to get serious, this is just a fling" but still think they will win me over. If they stick around long enough, or if they totally play it cool, or if they do this or that, i'll change my mind and settle down with them. When it doesn't happen, they get hurt. Sometimes they go quietly. Sometimes not so quietly. Either way, she feels hurt.

In the end, though, it doesn't matter how they leave. They all do, and I miss every one when they are gone.