Bets, Not a lot of time to post but I wanted to chime in...no whacks from me for going ahead with the mowing. I think it is important to go ahead with our plans especially when they disappoint us. We need to be moving forward always. The space was there for him to jump on board but he missed the opportunity. That should NOT keep you back.
He will notice that you went ahead with the lawn chairs and the mowing and you did NOT nag him in wny way. He will think about these ....he won't know what to make of them, necessarily...but he will think about them long and hard!
