From where I'm sitting, you didn't hurt your FIL by asking for the key. If he took it the wrong way, shame on him, i.e., after all you and your h are separated. You explained the reason for the request and I would now let it go. Get some additional keys made to have on hand and put them in a safe place. Don't give them keys to the deadbolt. They don't need them since you have a friend that watches your fur babies when you are away. If you and your h ever, and I mean ever decide to divorce, then change the locks. But for now, I think you explained yourself quite well and it's up to him to let it go.
You do realize that when you have "family" time which involves more than and hour or two, you end up w/moments of sadness? Why? Because you can see what life could be like if he would just wake up...but alas, he's not there yet and you are moving forward by leaps and bounds and he's still wallowing in MLC. Answers will come when they are ready, not when you want them. Everything happens in its own time for many reasons.
Pamper yourself a bit today.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
