I’m exclusively interested in the long-term, but I can’t speak for kink Tumblr in general… I occupy a very specific corner of it and seldom venture beyond my borders. Additionally, my perspective is further skewed because a lot of people turn to me for sanity-checks, so I hear more of the horror stories than the tales of blissful success.
With that said, you might be tracking the wrong metrics. There are people around here who are hobbled by super-toxic entanglements that lasted far longer than necessary, and in an environment where many are looking to be mindfucked, the line between lust and love isn’t merely thin… it’s a mental Mobius strip that twists itself into multidimensional knots.
What I’m getting at is that the heartbreak stories are real, but said reality is more complicated than “I was looking for love and he just used me for sex!” And based upon what The Youngs have told me of their adventures on Tinder and FetLife, I’m not sure Tumblr is anywhere among their top sources of problematic relationships.