gypsygal, Controlling who your H can introduce your S to can only happen as part of the D. In your custody agreement, you can put clauses relating to the introduction of OW to your S. For example, before he introduces them he has to get your approval, they can't spend the night, etc. etc. Lot's of restrictions that can only happen as part of the D agreement.
Your statement about this other woman "wanting your H", and "destroying lives". Well, on the surface it seems like it has very little to do with her, and everything to do with you H. In fact, the two of you are the cause of your own marital problems, not some outsider. Projecting your H actions on her, is shifting blame and denying the facts.
Also, you do not have to wait until the bankruptcy is final before filing for D. Those are two legal issues.
On another point, the whole fighting for spousal support is ridiculous. Kind of like fighting for child support. If you have been married 21 years, and do not work, then he is going to have to pay. Think in terms of 40% of his after tax income. So, you may not get 80% which would allow you to maintain your current lifestyle (that's a TV myth), but once you add child support (for 1 child can be 20%), then you are up to 60% of his after tax salary. The % can vary but this is the amount you can use for budgeting. Your not going to get everything, and he's not going to get away with giving you nothing or only a little. Go in front of a judge and no matter who's at fault (he cheated on me, etc) they will split everything 50% down the middle. Salry, house, everything.
The downside is that the support will only last a few years. If you have not been working, then you will have to find a job.