These are the things that I think are important in a marriage partner.
A growing person- someone who is working on improving his/herself and doesn’t just accept the status quo at any point in time (my husband told me he doesn’t strive to be a tzaddik, he’s ok with being mediocre. I thought this was a good thing, that he wanted to “perfect”being a beinoni before advancing towards tzidkus. I couldn’t be more wrong. He doesn’t want to take the responsibilities on that would enable him to advance. He learns b/c he loves learning, but it doesn’t bring him anywhere).
Emotional maturity – the ability to take responsibility in life:economically (to recognize a need and to do what’s necessary), socially (to look at oneself and see the role their issues play in a conflict. To acknowledge them, at least to oneself initially, and too work on remedying them. The ability to reach a point in time where one can acknowledge their own role and work on fixing it. The ability to work with another on resolving differences.
Good middos- being rochel and telling them nasty things said about them is not kind. I once went on vacation with my husband. He was upset about my weight gain and gave me such a hard time (this was 6 months after I gave birth) that I resorted to buying senna tea to try to lose weight. I had horrible stomach cramps from the tea on vacation (it’s a laxative). My husband does try to be supportive sometimes, but it’s interspersed with comments like that I didn’t belong sitting on the side of the table with the skinny people at a wedding, I should’ve been sitting on the side of the table with the fat people. How is that kind?
I’m sure there are more things, but for now those are the ones that come to mind. Maybe others would like to add their thoughts as to what is important in a marriage partner.