Just want to send some positive vibes your way and let you know I'm thinking about you. The "I'm sorry for these hard times" is infuriating, isn't it? It is such BS... like he wants some sort of reward for acknowledging this fact without actually taking any responsibility, or somehow can absolve himself by simply saying he feels badly things are "hard."
I know you are having a rough time and I totally get it. I did want to say, though, that I've been following you for awhile and it really seems like you have come a long ways. I feel like one step towards detaching is realizing you could be detached in a particular scenario, while still feeling the emotions it brings up. You are doing great.
And yay for him to actually be reading parenting books! (sarcastic emoji... plus actually it is nice that he is taking an interest here, I know all WHs don't). I think your attitude here is great too. Recognizing it is good he's wanting to be an involved parent and it is beneficial for him to feel empowered here rather than just following your lead. I like that you recognize all that and are like great, whatever.
You are really strong. You got this. Four is such a fun age. Focus on her.
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing