Right, except this should've been asked before and during when they were living together. Not after the fact. Living together is a big deal, or at least it's a big deal for most people and should be.
Usually when you live together, you want to split the expenses 50-50. It sounds simple, but many people consider how much money the other person makes or how much support the other gets from their family. In a smaller number of cases, one person may be filthy rich enough and not care and just pay as long as he/she gets something else they want basically.
You don't live together, and then just hope. Sure, since it's after the fact, definitely the question should be posed, but it is better to ask these things and other things of physical intimacy beforehand where the two people are in full understanding and agree to what they are getting and giving. It could be both agree to no physical intimacy (fairly to pretty unusual, but possible), but this should be ironed out beforehand.
l married someone, and lo and behold, bedroom romps were apperently not on the list, maybe due to several issues, l was never told anything.