The first question would be to try to determine why he hates your family. Do they mistreat him? Remind him of his own family? Act possessively toward you? Feel critical of him or of your relationship? If his feelings toward your family are based on individual issues of his, the most effective course of treatment might be individual therapy for him as well as couple’s therapy for the two of you so you can develop some workable solutions to the problem in the meantime. If members of your family are actually doing things to provoke him, possible solutions would be to have some extended family sessions with all of you and/or for the two of you to have some couple’s therapy so you can come up with ways to handle the situation together, so that you’re aligned as a couple and he doesn’t feel alone in dealing with it.