What do you think is important in keeping a BDSM relationship healthy? How does it differ from a vanilla relationship?
Probably mostly the same as vanilla. I feel like the biggest difference, and this applies to other unconventional relationship styles, is that there’s less of a script. Stuff that’s good communication for anyone becomes absolutely essential for unconventional relationships.
I heard of a woman once who thought all men liked blowjobs, and kept offering blowjobs to her partner, which caused tension until he finally got up the courage to sit her down and say “hey, I don’t actually like blowjobs”.
Now, not all men like blowjobs. But enough do that in most of her relationships, she could just go down and start blowing her boyfriend without checking first if he liked blowjobs, and she’d usually get a good response.
Now imagine if she was a spanking top, instead. If she suddenly started spanking her boyfriend without discussing his preferences, chances are very high that she’d get a negative response. And if she’s a spanking bottom, chances are her boyfriend will not spank her unless she actually tells him she’s into that. Even if he’s a spanking top, he probably won’t spank his partner without knowing her preferences.
This applies to more than just kink, of course. Most monogamous couples I know don’t have an explicit discussion about being monogamous and what that implies for their relationship, but ethical non-monogamous couples all need to have a discussion of non-monogamy. Most peri-allo couples generally assume that sex and romance will go together, and don’t explicitly discuss their boundaries in those dimensions, but relationships with an aro, ace, and/or repulsed partner need to negotiate the separation between those dimensions and what each person needs and can tolerate.
Ideally, everyone would discuss these things more. But couples who stick to the norms can get away with poor communication a lot more.