KLC I guess it depends on what your going to do with the house. Are you going to sell it ? Or are you going to keep it ?
If your going to sell it and half the profit from that then it is only fair that you both pay half of the mortgage , taxes and common household expenses for its upkeep. ( water , electricty , gas , insurance ) TV , Internet. That should be on you. Or barter for half of that as well.
General upkeep , barter that as well.
My wife and I agreed on half of all expenses each month. We agreed on the date that the money goes into a joint account that all expenses come out of. Any additional expenses need to be agreed upon by both.
We also set a sell date on the house. Then we will divide what ever money we get in half.
We did what was fair.
If it gets heated it does not affect your LRT. This is your survival were talking about here. Do not back down. Seek what is fair.