When I was doing in house, I looked at his salary and mine. He made 60% of the money coming in, I made 40%. So, I went down the bills and split them 60/40. Gave him the amount I expected in the joint account.
I split our groceries 50/50. After all, 4 of us in the house, he should pay to feed is kids as much as I, so it was 50/50.
I didn't have nanny expenses, but WTF are you thinking 20%???? Are they his kids?? Then he should be paying 50%!
I handed him the application to get his own gas card. He could pay his own gas expenses. No more using mine.
Etc.
Now, in your case, you have been paying all the mortgage payments, etc, but I think you will need to talk to a lawyer to see if that's enough to cut him out of the equity. I don't think it is. Any "rent" he pays will be looked at as his part of the household expenses, and you will owe him half the equity on the marital home when you file. If that's so, he should be paying half. If you paying the mortgage solely makes it you only owe him equity up to when he was contributing months ago, then keep it that way. Check with a lawyer.
Chores...I told mine that while he was living in the house Tues and Thurs (I picked two nights) he was responsible for feeding the kids, homework, etc. I made it clear I expected him to clean certain areas, etc. If he didn't keep it up, he could get out NOW. It's a little harder I think because you are both living in the areas, and what are you going to do if he doesn't?? Only recourse is tell him to leave.
On that note, don't let him keep going like this. TELL him he has until March 15 (or whatever) to get out. Give him a deadline.
As far as the rest (keeping the house, equity, etc) get thee to a lawyer.
BS(me) 46, Two wonderful teens.
He is no longer my best friend. Repeat until it sticks.
WH says marriage is over: May 15, 2009.
EA#2 July 20, 2009. Legally sep: Aug 16, 2009. DIVORCED!!!! Signed Nov 23, final Dec 24, 2010, adultery listed.