Ex Invited to Family Reunion

My husband's family reunion recently passed.  We didn't go.  It's out of state but I thought about just driving up for the day. However, if I am going to spend eight total hours (round trip) in a car to spend a couple hours with family, I don't want to stare at my husband's ex-girlfriend for those couple hours. Yes, she was invited. She isn't worth the $120 in gas it would take for this trip.