@kaia i don't know how it is in the US but here in germany I would only marry for the tax benefit.
I have multiple partners of varying gender and I would consider it rude to have a hierarchy like this in my relationships.
Legally one can only marry one person at the same time in germany but luckiky it doesn't involve the churche at all. It's just signing papers and paying a processing fee to the state.
It annoys me that being married has a reduced income tax rate than being non-married.