I thought I had typed out a response on my phone, but apparently I never sent it.
On the birthday party. I highly suggest going through with a joint party. While Josh is right that kids and family will need to get used to separate events in the future, there also will be joint events too. Graduation partiy, wedding, 16th birthday. Yes smaller events will be separate. But there are going to be some big events that will be joint events.
On the financial stuff. IHC, the decision is made, right? You guys are splitting up. So why would you do anything that combines your finances in any way? Though I have to say I don't trust her on the refinance. So just put the house up for sale, but put everything else on hold. When you D you will, with mediation and/or court help, split everything 50/50. You and she will get 50% of the proceeds from the sale. Half of all the debt. Etc.
And do not leave the marital home until the D is settled or ordered by a court to do so. Yes there are legal ramifications by doing that. Could impact custody, and whether or not you abandoned the house as far as who gets that and the equity that goes with it. Stick it out IHC. A few more months won't kill you.
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018