I was in your shoes 20 years ago. All my friends were getting married and having babies. Sure it hurt a little when I really thought about it. I had several failed relationships. But two days before I turned 30 I met the man I've been with for over 9 years now. No we aren't married or have kids, but...........we're happy!
He wasn't in the "ideal" category for me either. He is 13 years older than me and I thought it would never work. But with no pressure of commitment things have worked out great!
Of course we always get the comments "why aren't you married?" or "do you want to get married?" or "when are you getting married?" My usual answers are "because" or "it's not that important" or "maybe never".

Oh, and I always hated when people said this to me (but I found out it's true!), but "it will happen when you least expect it". Stop trying so hard and it will happen. When I met Bruce I had just ended a 9 month relationship and thought "there's no harm in just talking to this guy". We've never gone a day in 9 years without talking.
I also hated it when people said "you're still young, you have your whole life ahead of you". But now that I'm almost 40, again, I see it was/is true! Shoot, I still feel like I've got my whole life ahead of me, even if it is just a bit shorter.

Bottom line is just do what makes you happy. Not what makes everyone else happy.