I'm with ClaryFray on this...
I've always been kink orientated though I didn't know that's what it was until someone showed me the light.
My ex wasn't into it at all and unfortunately, it was one of the many reasons why I left. The worst was in the last few weeks he did ultimately try what I wanted but I felt nothing. That's when I knew I couldn't stay anymore.
I was fed up of a partnership where he took all the time and gave very little back. So I left.
We didn't have kids though... and that's where you're getting alot of flak.
People who are not kink-orientated will not understand the depth of those feelings you get nor the freedom you get from it. It's very hard to describe to those who are not into it. But it really is a lifestyle choice.
On the other hand, it really is pretty awful if you put this above your daughter. Putting sex above your daughter's needs would be awful. You can't really use that as a sole reason to leave or explore.
However... this will ultimately come down to your happiness. If you can stop resentment for seeping into other areas of your relationship and stay together for your daughter, then fab. Do that. But if you can't, and she sees you as very unhappy, I don't think she'd want that for you.
In summation, you're in a bit of a pickle and unfortunately, you won't get much sympathy from MN as the majority are seemingly vanilla (there's a few kinksters out there). If everything else is okay in the relationship, it's be very hard to justify leaving for the sole purpose of playing.