I'm no expert in this, but as a woman who is married, I can tell you that being a decent significant other does NOT come with gender roles. I'm a feminine woman not because I'm married to a masculine man. This is who I was before I met him and it's what I will continue to be with or without him. I'm me for me.
With that said, I get your disdain with making one character the "woman" and the other the "man". In a relationship, you are still yourself and that is the point of it working out. Being you and being loved as you are not following some kind of "role".