I agree. It all makes sense. Him staying with his mom and going to an off campus college house party (as reported), them appearing separately (him at Penn State, her at churches). No wonder she calls everything "mine" instead of "ours." Actually in her case it would be "ares."
Them on the couch has been strange for months. They use to be snuggled up. They haven't even touched each other, barely even looked at each other in the latest episodes I have seen. They have just not been shown together that much. Did she ever mention missing Jon or being glad he was back from Utah, or only Cara? She hasn't done her "oh honey" and touched his face or anything similar lately.
It is always sad when a marriage breaks down. I hope whatever happens is for the best.