Blood is thicker than water, meaning most people will always side with their family if push comes to shove. Testing this bond is probably a bad idea and could lead to a ruined relationship if you’re not careful.
One guy let his pregnant daughter move back home, much against his live-in girlfriend’s wishes. Unimpressed, his girlfriend has laid down an ultimatum: either his daughter moves out, or she will. Now the guy has turned to an online community to ask if letting his daughter stay would be a jerk move.
More info: Reddit