My brother in law marries a different woman every 2 years and?

I'm tired of going to his weddings. Sometimes the marriage only lasts a month. Here's my question, do I have to buy him a gift for the upcoming nuptials? I feel bad for the lady. It isn't the brides fault that she fell in love with a cad but I'm tired of watching him walk down the aisle every other year and spending time and money on his sick ***.