Regarding "YOU ARE NOT FUNDING HER ANTICS, PERIOD. Stand your ground on that."
So STBX is a housewife primarily, works 1-2hrs week just for something to do. I provide everything...car, home, insurance, spending money etc. Since her mom's passing this spring she has received an inheritance ($30k in May and $50k due around November - I know this because her sister told me (not my STBX) and because she owes me for her inheritance tax ($3600)). She has no willingness to share costs on anything except a meal now and then. She did demand that home improvements be done about 2 weeks ago and we go 50/50, but has gone away with no more talk of it. I give her $1k monthly for misc. spending. I usually get all groceries and household items.
Should I stop providing her $1k monthly?
For now I would keep giving her the stipend. What I meant by not funding her antics is not paying for her to have her own place, or paying for her GGW (girls gone wild) drinking parties or trips or whatever. If you've been giving her a stipend then I would continue to do so unless things deteriorate to the point where you want her gone. If it gets to that point then like Cadet said, lawyer up first.
Also if she talks about getting a new car or any big ticket item like that, tell her you don't feel comfortable making any big purchases given the current status of your marriage. If she ends up leaving you are both going to be on shaky financial footing for a long time, so start preparing yourself now. This is the one thing I wish I had prepared myself for a little better. I make a good income and just assumed it wouldn't be an issue, but I went from spending whatever I wanted to having to place myself on a budget and keep close tabs on it. I amassed a lot of debt in a short amount of time before finally getting a handle on things.
