Originally Posted by BoringGuy
You REALLY do need to work on your communication skills.
This! How is she supposed to know you need her to go home unless you tell her. You guys need a sit down with all three of you. It doesn't have to be nasty, but it does need to be firm that you need space and so much "togetherness" is stressing you out! Be VERY clear that an invitation for dinner shouldn't automatically be seen as an invitation to stay the night.
Once a week a group of us goes over to a friends house. On occasion she will offer her couch to any who want to stay, but other times, she just flat says "Sorry guys, but I need to kick you all out". Do NOT be afraid to ask people to leave your home when you feel the need for space. If you feel the need to soften the request, you could always follow it up with a dinner invitation for few days from now.
It sounds like you actually do like her company, just is much smaller doses than you've been getting.