@Marie1988,
One thing I want to point out at the start is that just because you've been with your husband for 7 years, it does not mean you need to be together another 7 minutes. It's the
sunk cost fallacy, where you feel you've put in the time, so things are going to get better if you just wait around long enough.
It's like the old joke about how in an enormous pile of horse manure, somewhere in there, there's got to be a pony.
So you don't have to hang around any longer, if things aren't working out. It's okay to call it quits. And you've already filed for divorce. So you're halfway across the threshold anyway.
Hence if you want to leave and pursue Kam, then you would be able to. Although if I were you, I would come clean to Kam either way, as that gives him a fair chance to decide if continuing on is worth it to him. It would be mature to be unselfish about this and give the guy an honest decision to make instead of him banking on a deception.
But if you want to stay, then make an effort to make it work. Not just hanging around as roommates and hoping it'll somehow get better. Instead, working at it should mean marriage counseling, both along and apart.
It also, unless you and your husband decide to open up your marriage, means that you say sayonara to Kam.
Or end it with both of them. There's that option as well. I know you don't want to lose this one or that one, but have you ever truly been on your own in the world?
Independence is an awesome thing. And it would be a good idea to have an actual physical break (that is, a separate living space) which would have the effect of telling the truth for you. If your husband wanted to fight a divorce, then he would see he'd have to do something to keep you. And Kam would see that, yes, you're separated.
Right now, you're at a stalemate, and it's far easier and more secure to keep up with the status quo. You get your **** buddy and the roof over your head. When it all comes crashing down, if you've done nothing to change the status quo, it will not be pretty.