Even if you are less assertive, that might be ok. I think it is enough when someone can show their colors just a little bit when it is needed.
In my case, I was bothered by his inability to be on my side when I was fighting his fight. If he played the dead instead of smiling and responding to the jokes a guy that he whined and bickered about for months, I would be ok with it, that is the level of assertiveness that I expect lol. We were not compatible, no wonder we got seperated.
No wonder you guys are getting married.