I am so sorry you are going through this.
A person can sub to a dom, but it is done with consent with the power exchange and since there's a husband and children -- I'm worried her dom is not a responsible dom. It's edge play, but it should not become child neglect! I get the high of subspace -- but seriously neglecting husband and children is just neglect.
Maybe she's an addict to all the feel good endorphin things going on with the edge play? Does she even want to recover?
It's a double standard here -- what is good for goose is good for gander. The door is open on your side too -- whether or not you avail yourself of that option. Her jealousy and whatnot -- is it really jealous of you? Or that she'd have to put time in holding the fort at home when you have dates and she doesn't want to?
I always state my oppositions to whatever she's proposing calmly and along with my rationale.. She goes straight into the arguing place.
If she's often BDSMing, does she have enough time to clear her system of the hormone soup? The fight/flight response and subdrop thing could lead her to GRRRR when you want to talk. It can take a few days to clear. If she goes out a lot -- it could be like you are living with an addict/drunk person whose thinking is impaired. It isn't an excuse for neglecting things at home, but I wanted to point that out because it makes things that much more of a challenge if you are trying to talk to her seriously.
At any rate, you do not sound happy in this marriage. I think you DO have to talk to her firmly -- about your wants, needs, and limits.
And you may need a counselor and it may mean navigating a decent divorce if she's not willing to work things out with you.
Again I am so sorry.