As someone else mentioned, you need to have a frank discussion with your partner. Generally speaking, when you co-own the house, you split it 50/50. Keep that in mind for future earnings, career goals, etc. Over time, there will also be substantial financial obligations for the home as well. How do you plan to pay for larger expenses such as a 10-15k roof, AC etc.?

For a personal anecdote, my wife and I’s income is close, but still about 60/40 (e.g., I make a bit more to provide 60% of our household income). If shit hits the fan, we split the house straight down the middle. My rationale was easy: if we did split up, I’d have a lot more to worry about than the house.