a jealous friend

So this is probably going to sound bad but there's no other real way to explain other than flat out say, I'm jealous. Sometimes they really drive me mad with how many guys they have at the ready for them. Before you say anything I totally know it's not their fault at all, and it isn't an issue of self-confidence. I'm actually rather happy for them, but it's still kinda frustrating. Every time they leave a relationship that's been pissing them off and they decide they're okay with being single for a while, anywhere betweena few  weeks to a couple months later here comes another one and shortly after that they're dating again. I mean them no hate but this is already the third or fourth time for either of them. At this age I know by now that I'm too old to even care, but sometimes it's the fact that we're this age that it bothers me so much (I'm pretty marriage minded and the way I'm set up I'm pretty sure it's gonna take me a long time to convince someone else of that). It just makes me sad sometimes that it's so easy for them and quite the opposite for me that's all