I find it unlikely that a dating website would share a dataset, although OKCupid Trends was one of the first good data blogs (and I'm glad they are back posting after being silent since 2011).
There was a Pew research study from 2013 - Online Dating
This data set contains questions about online dating, technology and existing relationships, and non-internet users.
(requires entering some info to download data)
Sample: n=2,252 national adults, age 18 and older, including 1,127 cell phone interviews
Interviewing dates: 04.17.2013 – 05.19.2013
The survey is quite long and the data is available in crosstab, csv, or spss formats. Included are questions and answers about internet usage, where people meet each other, usage of dating websites and apps, demographic information.