I once had a friend tell me that if he was a woman he would marry me. At first I found this "compliment" a bit disturbing for a few reasons which I won't bore you with.
It was not long after that revelation that he was telling me about a good friend of his who was going to visit. He described how they were a great complement to each other's personalities and that if he (the visiting friend) was a woman, he would marry him.
After I heard this, I started to wonder why in one friendship he was the woman and in the other he was the man. I didn't bother to ask, but still I wondered.
All the facts having been considered, I believe that it was just a way of defining each friends status in the relationship where gender was taking the place of a more socially acceptable ranking system. It was sort of like when I called another guy "Jennifer" because he didn't know how to string ethernet cable through a suspended ceiling. I was indicating his "little girliness" at stringing cable. Just a note to everyone who wonders, you don't push it, you roll it in a loose ball and throw it.
Some people have a family structure that they assign friends to, a mother, father, children and sometimes even extended family members. They relate to these people as having these same family roles in their friendships.
Personally, I've often found it a bit disconcerting when when someone would call me "friend" and then even more so when I was referred to as "best friend", so when "husband" was implied I was quite a bit taken aback. But I'm not really *too* disturbed by people making overtures of friendship anymore. I've gone from being fed-Up with People, to being tolerant of their seemingly haphazard methods of defining relationships.
So, I do have friends, and I am married to an actual woman, so hopefully that will preclude any possibility of marriage to a non-gay man-wife.