Could explain it. Like I say - just presenting an alternative to he's gay.
If you want to stay in the marriage but you need the sex to change - I would probably suggest you seek out some proper guidance/counselling. Or at least do some reading and research.
Like I say - he's not actually changed. You've changed.
But that's ok. You're allowed to change. At any point you're entitled to say this doesn't work for me anymore, especially when it comes to sex. But now you need him to make the leap with you and how you start that dialogue is crucial.
I couldn't imagine my DH coming home to me and saying - I need you to be a dominatrix after 20yrs of him being the dominate partner in bed. It would be so far out of my comfort zone that he would need to address that carefully with me and I'd need to explore it very slowly and ultimately I might not be able to do it. But I do value my marriage - so I guess I'd have to listen and try.
And I think that's what you need your husband to do too. How you get there needs to be handled with care and if you can't get there, then you need to be consider that you might need to leave the marriage.
But I do think it's crucial that you accept the role you've played because otherwise you will come at him from a place of resentment and anger and blame. He showed you who he was when you were dating (from what I can tell) you're now the person rejecting that side of him. That's not his fault.
But it's also not your fault if you need things to change now.
I know you're hurting because you've probably been going along with this for far longer than you were ever comfortable with and it might hurt even more if he can't change for you. But just try and come at it from a place where you take responsibility for how your sex life has developed, so that when you approach the conversation it's from a place of 'I need a change' not 'you need to change'.
I hope that helps and makes sense xx