Sometimes the wayward spouses behavior can be explained when you look at it in the context of his affair. What I mean is the affair relationship is his primary relationship right now. Maybe his OW feels a bit guilty as your wayward husband complains that you are keeping the kids from him and just generally victimizing him....so, in order to balance things out and appease her guilt and shame, he portends that everything is copasetic between you two. That really doesn't explain the more flirty texts but these kind of texts working out details of the cottage use could be used to demonstrate that you two have a working relationship that should only get better with time as everyone adjusts to the new dynamic.
Regardless if it's temperature taking or not, it's certainly not him "reaching out". He probably wants to travel to the cottage with his OW so figures if he either throws you a bone about going up with you and the kids (which he probably won't follow through on but can appease his own guilt by making the plans under the delusion that he can mends all the relationships over one weekend). In discussing dates he can also figure out the best weekends to sneak up there with the OW when you are otherwise preoccupied.
Ya know...when you go dark, you won't have to speculate and decipher these messages anymore trying to figure out what they mean and how you can derive hope from them. Until he ends his affair there is no hope. NO CONTACT with OW is step one to hope. Everything else until then is just flak.
The internet is 90% complaining and entitlement and I hate it because I deserve better!