This question is actually a little freaky, solely because of the fact that Mom and I just finished having a conversation on this very topic.
Things like this have been happening a lot lately.
Day 18 -- An important trait in a potential spouse.
This would actually be a little hard for me to narrow down. I have a list in my head of traits I like, but deciding which would be the most important out of all of them is difficult. Mostly because I don't know if I've decided yet. And because one trait does not the man make.
That being said, my Mother reminded me of one single trait that I do believe is of paramount importance. And that is "he must love God more than he loves me." My Mother has such a wonderful way of being able to both articulate the core of a concept, as well as expound upon it. I myself ramble endlessly, as you have no doubt noticed, before I can finally manage to come to the point both out loud and in my own head.
Loves God more than he loves me. I would also label that as integrity. A man who loves the Lord more than anything is going to have a strength of character unlike any other. There would be other necessary factors in a potential spouse, but without that one foundational trait, none of the other factors would matter.