Most Helpful Girl
Yes, it can definitely make or break a relationship, depending on how close the girl is to her family. However, personally speaking, I would still be objective. I would hope my boyfriend and family would get along well but If my family disliked him and did not have a valid reason, then I'm probably not going to take their complaints seriously.
Most Helpful Guy
Tremendously. In a long term relationship, it is absolutely essential for you to have the acceptance of her family, and for her to have the acceptance of your family. If there is resistance from either family, you will be fighting pressures that the family will exert, and one of you will be torn by feelings of loyalty to your partner and loyalty to your family.