Buddhist perspective on cousin marriage
Buddhists have the most relaxed marriage laws of any religious faction. In fact, it may be more appropriate to say they have no marriage laws whatsoever. Buddhists see the institution of marriage, and nearly all matters of the heart, as very private matters, to be decided solely by each individual.
Some may find that surprising, as Buddhist monks live a life of celibacy. Yet, even that choice is made by the individuals out of a sense of personal dedication to serve others in spiritual aspects, not out of a prescribed religious duty or requirement. It is simply a lifestyle they have voluntarily chosen, just as vegetarians in some cultures have chosen to not eat meat.