I've tried so many and the only one that works for me is
http://www.thedatingstudio.com
I don't have a hell-of-alot of dating traffic, but I've always thought that it goes hand in hand with porn so I advertise it with IM pops here and there.
Some numbers for the last 12 months:
Total 52 £734.95 71 £1325.31
52 is initial sales
71 are rebills
Not something that makes you rich, but nice to have on the side. It's on auto-pilot. Create a few whitelabels and slap up some links *shrug*
They don't have a ton of dating "niches" though. LMK if you have any questions.