<prompt> Human: Hello everyone, Personal finance marriage question. Marriage is a distinct possibility for me shortly, and Ive been told numerous times how people were shocked by how much their monthly expenses as a couple went up compared to their monthly expenses when they were both single. In other words, they assumed 2 2 4, but really it turned out 2 2 5, or 6.Heres my question: Under what circumstances would two people, who were financially self-sufficient living alone, steady income, no excessive debts, car, car insurance as single people, have more monthly expenses than they logically thought they would? Shouldnt combining two single persons monthly expenses roughly equate to a married couples monthly expenses? Assuming both people retain their steady income as before marriage. Where does the extra factors come into play if both members are able to pay for their own needs as it was before they were married? Thanks for your input!  <response>: lifestyle inflation, kids, more takout, etc... Itd be different for anyone, but really it comes down to lifestyle. For example, buying a bigger house to plan for the future, more vacations, any number of things. 