ᐅ Buying a House with Friends: One Party Getting Married Before the Purchase

Hello, my colleague and I are planning to buy a house that was recently offered to us at a very good price. Since we know the sellers and they are not in a hurry, we still have some time. Both of us are currently single but in relationships. After purchasing the house, each of us would like to move into an apartment with our partners. According to financial advice we received, we could apply for the mortgage together (without our partners as well). However, one of the couples is getting married later this year. Does this mean that the married party must sign the purchase agreement together? If financing with my colleague and me is not an issue, does the future spouse still need to meet all creditworthiness requirements? (For example, a permanent employment contract, which is not currently the case due to a recent job change by the future spouse.) If that is true, would it be advisable to postpone the wedding until after the house purchase, since buying the house might otherwise not be possible?

Best regards