Whenever DH and I go to my parents for lunch/dinner I automatically help my mum prepare/serve/tidy away. My DH automatically sits in the living room with my dad and chats. I don't mind this as I'd rather stand and chat to mum, and he'd rather sit and chat to dad. When it's time to clear away my dad never takes a plate through, my mum does it, and I always help because I want to help my mum, I don't want her to have to do it all. I always pointedly look at DH and he starts to clear too.
However last weekend we went to the in-laws for lunch for first time in ages. After we had eaten, MIL and SIL started to clear. BIL, DH and FIL sat on their arses and stayed chatting. My overwhelming instinct was to get up and help. But I didn't because I just thought fuck it, why does these 3 mens penis excuse them from helping? So I stayed and chatted with them. But I felt so mean for not helping. I'm sure the men didn't feel mean at all. Should I have helped? I feel like if MIL wanted a hand she could always have asked her husband, and co-host, to clear the table with her!
Dh is a bit like this at both his parents' and my mum's houses. Drives me a bit nuts! I usually offer to help, dh sits chatting to the other men, looking at his phone or reading the paper. He pulls his weight at home so I'm not sure why he's like this elsewhere.