For me it’s foot fetish stuff. Every damned thing else is on the table but before I could make the lethal mistake of talking about it, she expressed her giga-ick about the issue. To this day I thank God I saw the metaphorical fly hit that electric fence before I walked into it.
No, I don’t keep secrets from my partner. But we do hold each other’s privacy as sacrosanct, which requires a balance. We are monogam-ish and currently want things to stay that way. When one wants monogamy, the implicit corollary is assumption of all responsibility for a partner’s sexual satisfaction. The “mono” and “-ish” parts require maximum reasonable transparency, communication, and self-awareness so that we are all fulfilled and and informed.
Through a few decades of dating and many imploded relationships, I have found that being open with my partners is the surest way to get exactly what I want. And I’m seriously twisted and pervy.