Hi Brit. I see a lot of my own situation in your story (though my WAW's are a bit more extreme.
Nevertheless, she followed a similar pattern. Decided unilaterally (before she advised me) that we were done. Then went out to seek attention/date (somewhat secretly). When I found out, she told me she was doing it to be happy. She said she still loved me and also wanted me to be happy and that I should go out and find someone who would help me with that. She said it was clear to her that she wasn't that person.
In response, I, like your husband, have made positive changes... lost weight, found friends, took up hobbies, improved things for myself at work. These changes were not to impress her, but to occupy myself and take my mind off the anxiety and disappointment I'm feeling. After six months, I'm off the sleeping pills, focused on my future plans (which don't include my WAW) and being the best Dad I can be. I'm actually excited about finding and setting up my own home in a new place and the opportunities for new friendships and relationships that will exist there.
Through the process of detaching and GAL, I've learned that happiness comes from inside. You can never rely on anyone else to make you happy. You can share happiness with someone, but can't rely on them for it. Either you're content with yourself, or you're not. If you're not, your unmeetable emotional needs will wreak havoc on the lives of those around you.
As I said, I'm moving forward, making my own plans -- laying the groundwork for changing jobs and countries. Now my wife will have to make career and parenting choices based on MY choices. She exercised her free will. Now I exercise mine. It's not a punishment; it's what I need to do to enhance my life and happiness as a newly single person.
She seems to have thought she could have the best of both worlds... continue to rely on me selectively for her emotional needs, lean on me financially and as "co-parent" while she goes out and seeks my 'replacement'. I'm not having it. Things won't be on her terms. Full stop.
I suspect this is some of what your husband felt, too. He came to terms with your choices and moved on. Now you have to come to terms with his choice to do so, and the fact that he GAL. Sorry if that seems harsh, but there are consequences to every choice.
I'm convinced there's little chance of reconciliation between my WAW and I (not that she is expressing any interest in reconciliation). She says she wants 'amicable' separation... still wants me in her life when it's convenient, but also wants her idependence.
The thing she (and all WASs) need to understand is that, as the LBS, it's my choice whether to forgive/forget/be friendly. Betray us, lie to us, cheat on us, cut us off... we will go away... but realise that's what you asked for and be big enough to deal with it when it finally happens. You can't have it both ways.
I may or may not want my WAW in my life to some degree (beyond sharing parenting responsibilities). I haven't decided. I'll decide when I'm ready, and let her know then.
Some of the best advice I read for a LBS was in "Codependent No More": I'm paraphrasing here, but it was basically, detach (lovingly or not) but move on. Forgive or not, but move on. Cut the purveyor of your pain off; don't allow them to hurt you any more.
A few posts back, you asked for a man's opinion on what it would take to rebuild things. I've been thinking about relationships alot lately and here's an analogy that's come to me:
Building a relationship is like building a house. The foundation is trust... something you develop as you begin dating, get to know each other, start spending time together and intertwining your lives. On that foundation of trust, you begin to build a structure -- a network of shared friends and extended family, marriage, kids, shared responsibilities, interdependencies, an orchestrated way of doing things day-to-day based on each others' strengths and needs. Over time, the structure grows and it becomes MORE complicated to maintain.
It's like adding rooms to the house... it becomes more of a responsibility to take care of as it grows. But make no mistake, you need to take care of it or it will fall into disrepair.
So you'll need to do maintenance and make fixes along the way. Every so often, you need to do some major spring cleaning or a full-out renovation to keep the structure sound and make it a nice place to 'live in'. In relationship terms, that means making adjustments in the ways you interact, maybe seeking therapy when you hit a rough spot, etc.
When someone walks away, though, or cheats, it's like blowing up the foundation of the house. The rooms (i.e., the day-to-day routine and interdependencies, financial support, family relationships, etc.) fall down as a result. The relationship can't hold up on their own without that foundation of trust.
To reconcile, you need to rebuild the foundation... that means rebuilding trust. For me in my situation, that would mean my wife showing genuine remorse for the things she's done. ("Sorry I made you feel sad" doesn't cut it). She will have to be an open book with respect to her whereabouts, her online activity, her spending, etc.
After the foundation crumbles, to rebuild you need to go back to the beginning... start giving a reason to trust again through transparency and openness. You need to reaffirm for your spouse the things you appreciate about him/her. The material is all still there, you don't need to quarry it anew, you just have to begin to reassemble the rubble into a solid form. It takes hard work, and it takes time.
I wish you luck. And I only hope that one day my WAW will be willing to start rebuilding, like you seem to be willing to do with your H.