You don't really want to "build links" you want to earn them. Links earned are worth 1,000x more than a link built.
Sticking out as a dating site in this day and age is a tough one. You really need to make your site unique. You need to do something newsworthy... if your focused in a geographical area. Do an infographic about that area, or conduct a survey and share the results.
Now with all that said if you're still looking for "link building" offer a coupon and share that coupon on reputable coupon sites... but then again those links are "earned" since you're offering something.