I have already been put in the situation, right before I was married. I look at it like this, my wife and I are joined, we are soul mates, we are part of each other. To be forced to make that choice is like asking me to chose myself or my relatives. Their is not question, I chose my wife over anyone at anytime.
I have also found myself in this situation, I chose my girlfriend and for 2 years she told me how my family was "out to get her" and my family told me how she was taking advantage of me. I chose her over my family. Then she left me so she could have 4 guys and not feel guilty about having a boyfriend. My family has graciously not held it against me. I would have to say, if my girl can't accept my family, she can't accept me.
I chose my current wife over my family. Basically, they (my family) did not agree with us getting married, and chose not to come to our wedding and support us in our decision. I could have chose to not get married, or try to reach some agreement between her and my family, but chose instead to marry her and move on with my life. Best decision I ever made.
Same for me Malexander! My family was not in agreement with my marriage either and I decided to go ahead and do it anyway and it was the best decision I ever made. He is the cutest and sweetest man on earth.
Thankfully my family approves of my partner! For me this isn't a matter of choosing one over the other. It's more a matter of doing what is right in a situation. If my family are completely wrong about something and are against my partner than I will stand-by her. But if the roles were reversed I would let her know that I didn't agree with her.