I agree.
If you really want to define a marriage, however, all you need to do is take on your hubby's last name.
Partnership are subjective. There are way too many ways to define a partnership. The matter would become too complex and convoluted if LL was to try to expand upon the partnership box in profiles. That said, where there is a will there is always a way. But it isn't really necessary as LL provides enough narrative space in either the "About," "Picks," or "1st Life," pages to explain the partnership if one so desires.