Relationships in general

I doubt anyone can argue that relationships are easy. They're messy, difficult, bruising, and paradoxically beautiful and fun.
I've been hearing from a number of frustrated friends lately. About? Boyfriends and girlfriends.
It seems to me that, in one's twenties, a lot of people I know and have befriended have swung either one way or another. Let me explain. Many of my friends have proclaimed their immortal love to their boyfriends or girlfriends, going as far as marriage, while others have shied away from any relationship, continually saying: "I like to keep things simple. I don't want to put a label on our relationship."
Translation? I want to see (aka go to bed with) other people. I want to see you, but I want to see other people.
Why does this make my blood boil? I'm not sure. After all, we are in our twenties, this is the time to party, to experiment, to live life to the fullest. However, to use an excuse as "I don't want to put a label on our relationship" seems weak to me.
Love and sex are a mess, it seems, for this generation, and probably for a number of others. Don't get me wrong, sex is definitely important, but so is love. What confuses me is that many of my friends ask "have you done it?" while few, is any, ask "are you in love?" Has love become obsolete, kitsch, ridiculous, embarrassing?
Well, that's the extent of my thoughts on relationships. Comments anybody?