I'm hetero, so I'm not sure of your motivations long term, I'm assuming your wanting a hot partner for life like the rest of us. Anyway, why ruin a hot good thing. It's alittle bit more sexy nauty when you don't see his dirty socks or have to worry about his needs 24/7. Or if you are lucky enough to be a diva he might not like having to tend to yours 24/7. I'd vote no. It's really difficult to untangle when you live together. I'm not familiar with ore nup terminology...but it sounds like a conversation that could inhibit that fantastic sex.
Actually, forget everything I said, I know nothing about what would work in your scenario, I was trying to make a parallel scenario based on my hetero experience. You do what makes you happy...you sound a long way from marriage....but that's ok as long as everyone understands that.