I`m gonna try to explain what happens quick and simple. If anyone had the same problem, I`d like to know
One of my male family members got married, then passed out. I could still use his wife for political purposes, until she got married to a noble from other families. Both characters disappear from the family tree, hence we can`t directly do any political actions. They are not either on the family tree or other nobles tab.
I can still see his stats if I get to it through the campaign map (he`s a general), but it`s annoying getting low loyalty messages popping up and not being able to do a thing about it.