I have a few reactions I'd want to give but I don't know if most of them are actually going to be helpful to you. Asking "Are you f-ing serious right now?" is my gut instinct and probably why I'm still very much in limbo...lol. Seriously though that's just going to poke the bear. It's probably best to respond with a shrug emoji and then say "You gotta do what you you gotta do." He can take that any d@mn way he pleases. It could be you are doing what you need to do. It could be he should do whatever it is he needs to do. That stopped being his business the second he fired you as his wife. Why does he care? He can't be looking for your blessing to sleep with other people. He's already gone outside your marriage without your permission. What could possibly be different now? He walked away. That means no more besties. He doesn't get your inner life. And he sure as h3ll doesn't get an explanation about a budding romance/friendship/chatting with some guy, what ever it may be.