Is it ok for your fiance to wear only boxer shorts to answer the door when he knows it's his exGF at the door?

My fiance, his daughter and I were just finishing breakfast. He had informed me that his exGF would be over to drop off clothes for their daugher in preparation for her birthday party later that day. When she arrived, he had seen her approaching the front door, he unlocked the door in only his boxer shorts. When my oldest daugter comes to visit, he puts on more clothing. Am I just being a prude?