I met Hubby, Bouncer, and my two ex-boyfriends on AdultFriendFinder, though people will say that AFF isn't supposed to be a relationship site, it's supposed to be a hookup site. (It doesn't work that way in my area, at least; Hubby and I are one of eight couples I know personally who met through there and are now either married or living together long-term.) I met Woody on OKCupid.
As for Fet, I've seen a lot of folks on there who seem to be in your age range, but I'm not sure where they're located since I don't check out profiles in general. Some of them include their ages when they post in groups. But if you ask folks on Fet, they'll tell you it isn't meant to be a dating site of any sort; it's supposed to just be a resource to connect with like-minded folks online and maybe find events in your area that you can attend to meet people in person. So you might want to use Fet to find munches, etc. in your area and try attending those to see if you can meet someone to date.
And as Dagferi said, if you two are trying to date *together*, you're going to run into more difficulty than if you were each looking for your own other partner.