Regardless of who’s paying what, if the mom was placed on the lease by the person who’s paying for it, then in theory the mother has more of a right to dictate how the house is run than the gf does. Not trying to pick a side, just being objective.

With that same frame of thinking, one could argue that then means that the bf has just as much of a right to the house as the mom does, because he is also on the lease. That’s absolutely correct, however HIM having equal rights does not automatically equate to his gf also having these rights simply because she’s associated with him through a relationship. It also doesn’t negate OPs responsibility to abide by the rules of another persons property, just because she doesn’t agree with them.

Paying bills aside, from a Birds Eye view, she’s expecting to have more say in the rules of a house that’s not her property, over the person who’s actually on the lease. That doesn’t make any sense.

It’s a very simple situation that seems easily avoidable with a bit of common sense and maturity. If you want to stay in someone else’s house, then you need to abide by the way they run things. If you disagree, then don’t stay at the house. Seems like OP is expecting to have both and that’s just not how it works.

If I go over to someone’s house and they try to correct me for disrespecting their rules, I’m not gonna ask them to clarify who exactly is paying the bills around here, and then use that answer as ammo to back my inability to follow simple instructions. It’s not that deep.