As ROmanoi you can role play as the pater familiae deciding wich is thebest men to marry your dougther, do not marry her to the first one that appears, usually this is rewarded with better husband options. Do not know if it is relly related but looks like so, whenever you do not have enought adult males in your family the AI gives option to adopt someone. After adoption he will be a male family member. Other way to do RPG with this situation is by recruiting generals and roleplay them as members