I see some similarities with my situation, let me offer a few words.

1) Yes, he's sleeping with OW, 99 out of a hundred chance. Don't let him gaslight you. Rarely, some men may blow up their marriage over just a "crush", but they usually don't move out until they have someone waiting - and the OW doesn't usually quit her job! Get tested for STDs.

2) Think of your H like a wolf caught in a trap, chewing his leg off to get out. He felt depressed, he tried changing jobs, that didn't make him feel better, he looks around, it must be YOU making him feel bad, right? (Btw, his therapist is a terrible therapist. Unfortunately this is not uncommon.)

3)
Quote:
That I deserve someone who is inspired to be a good husband and he just isn't. He's right, I'm well aware of what I deserve. I just know that guy is still in there, somewhere.
My ex had an affair when he was 40 (first MLC), we reconciled, had several good (excellent) years, then his MLC returned when he turned 50 and he left. One of the things he said when he left was that he was leaving so that I still had time to find someone else better for me. Made me furious at the time, but you know what? He was right! I DID find someone who treats me like a princess every day, much better than my ex, and dating in my mid fifties was tough enough, I'm glad he didn't wait any longer. I suspect dating in my forties would have been even better. Frankly, I didn't realize how much of my daily energy was going in to making things ok for my ex and walking on eggshells around him, until he was gone. Now in hindsight I realize that it wasn't just his depression (actually probably mild bipolar in his case) but that he also is a narcissist. It's early days for you, but resist the temptation to look at your marriage through rose colored glasses. Evaluate honestly whether he really was that great a partner. Did your friends or family have reservations about him?

4) Don't wait around on him. Live your life AS IF he's not coming back. Make your decisions for YOU. Spread your wings, try new things, meet new people. He's actually more likely to come back if he thinks he might lose you, and you're leading an interesting life that he would like to join. He's much less likely to come back if he thinks you're waiting there patiently pining for him, the ever-available Plan B. (You can always decide whether you want him back or not when/if that time arrives. Just don't put your life on hold, this may go on for a long time.)

5) If he is being generous in the separation agreement, consider converting it to a divorce now. (Unless, in your state, the separation agreement will automatically convert to a divorce with the same financial settlement details?). They are usually MOST generous in the beginning when they are still feeling guilty - after a fairly short time, when the financial realities of two households sets in, they usually become shockingly stingy. Get the best financial deal you can for you and your girls. Think of it as preserving family assets from the MLC, if he does come back later he will thank you for not letting him squander all the money. Divorce is just a piece of paper, you can always get remarried if you reconcile, but you were wise to start the ball rolling to preserve your financial rights.

6) This is not about you (and he is rewriting history, don't believe him when he says he was never in love) BUT - this is a unique opportunity to look at yourself clearly and embark on becoming the very best YOU that you can be. (True story - when my ex finally left, I took up playing the drums at 53, and have played in a pop-punk band for 6 years, AND have my first official recording credit playing vibraphone and glockenspiel on a professional songwriter friend's new album!)

7) Keep your expectations zero, stick to the high road and never bad mouth him to your kids, and remember your girls are looking to you for an example - show them how to rise above. (and yes, the oldest may blame you for not being able to keep daddy at home, don't worry, she'll understand eventually. My middle child was closest to my ex and we had that dynamic as a teen; in her twenties she now totally sees her father for who he is and is endlessly grateful to me for being the rock.)