I do enjoy giving that kind of service, as a cock sucker and a bottom, it's a pleasure for me to give pleasure. This is a complex thing as a bisexual, the giving and receiving, and I could talk more about this in the right forum or thread if you want to know. It's enough to say here that I'm fascinated by cocks, I enjoy feeling them, sucking them and feeling them inside me, and I enjoy the psychological satisfaction and connection of pleasing a cock owner.
I don't feel that I've ruined anything. They're seeking out a mouth or ass, either out of curiosity, a secret gay desire, or simply frustration or desperation to be pleasured by another human if they're not getting it at home. For a married man to go through with that, he's likely to have played it out in his mind and assured himself that it's what he wants, visualized himself doing it. I'm only making it a reality for him. How he feels about his relationship, or about his sexuality, is for him to deal with. I'll keep his secrets, and I'm happy to chat it through with him, but I'm his cock sucker / bottom, not his therapist. If he gets his cock sucked then realizes he's not straight any more, that's not be ruining anything. All I've done is help him along his journey. I see it as a harmless win-win situation: we both get what we want.