I have a SIL like that too. I'm always uncomfortable when at their house. When he is at our house for a family get together, he seems bored. He's quick to ask me to have the three children when he wants to arrange something for he and DD. I'm spending a few days with them in a holiday apartment later this year. I'm a bit apprehensive, but it's only for five days. It's an opportunity to go to a city, quite far away, and not be totally on my own. I'll do my own thing most of the time, and keep out of their way as much as possible. I'll pay for a third of the apartment cost, even though I'm only there for half of the time, so at least I'll be benefiting them. The kids are always ice breakers.