the best paying mainstream dating offer on the net for the past year has been promoting true.com and american singles
Primary ads and azoogle both offer these programs to promote, (you can't promote them directly this is the affil program). Both companies are good and very well established and pay on time every time.
You will earn 4.50 per free account for True.com and I believe 3.50 for american singles ... i've been promoting these pretty heavy for a long time
any questions let me know
good luck,
Primary Ads,
http://1.primaryads.com/
Azoogle,
http://www.azoogleads.com/