This is NOT easy, and anyone who hasn't gone through it doesn't understand. Sometimes, even some of the ones who have gone through it forget how hard it was.
Plus, everyone has their own way and own timetable for grieving.
So try to ignore when your mom or anyone else tells you you should be over it. Know that it is likely because they see you hurting, they love you, and they just want the hurt to stop for you.
And there is nothing to be embarrassed about. You aren't the problem. He is broken. He is the one who has done this. You are the one dealing with the aftermath.
Don't be so hard on yourself.
Having said all that, I'm going to give you a gentle nudge.
First - your IC says you are making progress, yet you don't feel like that's true. That is exactly what you should be telling the IC.
How much DO you tell the IC? If you aren't getting it all out, your IC may not be able to help you as much. If you haven't been telling her(him) everything you have written here, think about printing out this thread and taking it in to your next session. Write down all the bad things you are feeling, and take them with you. Then, if you need to, you can just read it to the IC.
Has there been any discussion of ADs? If not, bring that up with your IC and see what he/she thinks. There's no shame in using them, and it wouldn't necessarily be for long. Some people need them to get through some of the harder parts of this stuff. Honestly, when I went through my S and D, the first time I saw my primary physician after it all started, he asked how I was, and I lost it. And once he heard what was going on, his first question was if I wanted ADs. I took them for a while, but eventually I knew I didn't need them anymore.
Another question is this: is every 6 weeks for the IC the most you can do? If you can do more frequently, maybe you should think about that too.
Also, remember - there will be good days and bad days. The unfortunate thing about the bad days is that it's hard to even remember that there WERE any good days. You are convinced there will never be any good days again. If those feelings are overwhelming or too frequent, that's probably a sign you could use ADs to help you through for a while.
But you WILL have good days again.
And if bankruptcy is what you need to do, then do it. Plenty have, and you come back from that too.
More than anything, though, it sounds to me like you really, really need to go NC. Contacting the OW, knowing all this that is going on with him, letting him continually give you false hope - all of that makes it not just difficult, but impossible for you to get out of this mind frame where all you can see is what you have lost, and not all that you could have ahead of you.
You sound like you are doing mostly the right things. You just need to get your mind to follow. Part of that is quitting the "fix" of knowing what's going on with him, with the OW, and of letting him continually give you false hope.
Someone who is a "good man" doesn't do this. He might have been a good man once, and maybe, if he ever pulls his head out of his a$$, he might be again. But he also might not. Right now, and possibly forevermore, he is a complete a$$hole who is taking advantage of you to stroke his own ego and to keep a fallback position.
Don't give it to him anymore.
You'll have times you slip, where you'll contact him, or seek out what is going on with him/OW. When it happens, you just need to get back up, and go back to NC.
I know with kids you can't completely NC, but contact really needs to be limited to things about the D and stuff about the kids - and even with that, only what absolutely needs to be shared so you can both do your jobs as parents.
Do you have a friend that could help? Or maybe your mom (depending on what your relationship with her is like)? Someone who can help screen your contact with him? Because you should, as much as possible, make any contact necessary through e-mail. It gives you a record of everything going on going through the D. And then, if you can, have a friend/your mom look at the emails first, and screen out anything not necessary. They can just tell you when necessary that you need to re-iterate with him that contact is business only, nothing personal.
I know this has been a long post - I hope some of it will help.
Just remember, more than anything, that you can and will get through this. Things will get better. And do your best to stop following what is going on in his life, and instead work on you.
It sounds to me like he has done a real number on your self-esteem. That's what you need to work on. Realizing that the stuff he has done and is doing has nothing to do with you, and everything to do with the kind of person he is.