They sound lonely. Which is strange to say since they are in a couple, but I've been guilty in the past of overstaying my welcome just because I was desperate to hang out with people, and this sounds similar. I'll bet that they don't have other (or many other) couples whom they consider friends, and don't get out much. So they just want to hang out and have a good time. Or else this is just what they are used to in their friendships. Believe it or not, sometimes people do get together for lunch and stay all afternoon--just did that with a family friend last weekend. And sometimes people go out for dinner and sit and chat for hours--just did that with a good friend earlier this week. The thing is that these people have either been in my life since I was a fetus , or they are incredibly close to me. I guess I would suggest that, if they want to get together again, you be very clear about your boundaries. Give them a specific timeframe. "We can meet for dinner from 5-7, then we really need to leave to go (wherever)." Or just be honest and tell them: You really enjoy their company and want to continue the friendship, but you're having a difficult time figuring out how to tell them when you want to call it a night without hurting their feelings.