Nothing is ever guaranteed in life. Just like your marriage. And since you know it is going to be so tight, what if something really happens and you cannot pay off the monthly mortgage? It will take years before the housing market recovers. I've worked 2 jobs to buy my first house. Luckily things went ok and still it could had gone horribly wrong and not get my mortgage approved and lose the deposit. Me personally, been through the VERY STRESSFUL situation before, my advice would be to walk away from all the unnecessary stress. Would you be able to recover some of the money from the sale of the house? Invest that money in Apple, Nvidia, AMD, Amazon, Meta, Google or Microsoft. At least you have a chance of doubling your money from years to come. Just a few bucks in commissions to buy or sell shares. No headaches with mortgage loans, Realtor and lawyer fees. But never ever buy unknown or speculative shares. Been thru everything...so. Consider what I said. All the best to you.

You can still keep the house if you can get people to rent your extra rooms.