No I fully agree I have no control over that at all. But by having a open transparent relationship where we do talk about everything including sexual fantasies and we agree together what our relationship looks like together you can lay out boundaries. Someone hiding or unwilling to have that depth to the relationship I wouldn't be in a relationship with. Eventually things to come out in the open.
How can I give my consent to have sex with someone if they are privately masturbating and fantasising over animals, violence or children. I think most of us would not want to.
Can I ever truly know? No I can't see into someone's head.
Usually Someone hiding that eventually shows themselves in some way or something feels off. I do trust my gut with this. Those things don't go away like op is seeing.
For us personally that also includes other people and pornography.
So my husband and I have agreed we don't fantasise about anything but eachother. We prefer sex over masturbation so that's what we focus on. It's a choice. A preference we are utterly uninterested in anything else and see it as a waste of time.
Neither of us are interested in hiding parts of ourselves from eachother. We are open to exploring and trying new things all the time but we both have to be in agreement obviously.
Ofcourse all this time I could be secretly fantasising about something else no one can truly know for sure but what a bloody boring life to hide when I could be out living it if I so wanted to or equally it my husband could well be into it. So we'd just chat about it.
I appreciate its a different way of being in a relationship and others prefer more privacy and autonomy. That's great for them. It's just not for us.
I'm certainly not controlling or forcing anyone with my boundaries that's not how healthy boundaries work at all.
My husband is welcome to leave at anytime or discuss changing anything we currently do.
So yes I see it as my business who or what my partner fantasies about because I want to know them fully. I want to be able to consent fully to sex. Maybe it's something we can share who knows.
I can't fully police them no but I can observe behaviour. if signs are showing up of pornography use they have secretive behaviour or things feel off then no I want to be in that relationship and they would know that from the off. I'm very clear.