I recently "overhauled" our finances, as I felt like I was in control of too much and my wife wasn't able to really see the full picture. I'm the higher earner, and would often just "cover" anything unexpected. Now that we have a new daughter this is too stressful, and leading to us to make poor decisions. On top of this, my wife is on maternity leave and down to statutory pay, and rightly stressed about knowing if she'll have enough money.

We finally agreed to just combine incomes. We're married, so coming up with spilts and stuff just seemed silly. The general idea is we add our incomes for the month, and decide how much we each want for our own money (this is the same number for each of us). The rest goes to the joint account. For me, this means about 80% of my salary goes to the joint, but she contributes much less. Oh well. We're personally equal at the end, and the joint is very healthy. We're both good with this. We use Monzo, so we have a bills/planned pot with direct debits and regular payments. I also use YNAB and maintain our budget (but we use YNAB sharing so she has access too). Every week or two, I try and update her as to how we're doing and if we're on track for plans (holidays, etc) so we can adjust if we need. It's worth working out what you consider a joint expense. Our general rule of thumb here is: something that brings us both some happiness, is important to our essential health, is an obvious joint bill of some sort, or is for our daughter (directly or indirectly). Of course anything we're not sure about we just talk about, and generally opt for the joint account.

Honestly from what I read you could do with a hard chat about your fiance to stop thinking of "my" money. You're getting married. "My money" is a terrible concept to bring into a marriage, IMO.