Praying, sorry you found yourself here, but there is some incredible advice available throught these boards. First thing to do is to relax (if possible.) One thing that comes up over and over on these boards is that time is on your side. Don't make any drastic decisions right now.
I can relate to many of your points as my wife did this to me in July. This was after 18.5 years of marriage. I too was/am close to her family. One recommendation is don't do anything that can embarrass your spouse with his family. I made some poor early choices which really upset my W and set us back quite a bit. They were my fault and I took full responsibility for them. Critical point - no need to discuss the sitch with them. You want to avoid them taking sides. One of my issues is that my in-laws appear to be Team SSGA. This is not true as we have had discussions about it. They are really team - the kids and what is in their best interest? So be careful on that one, but don't give up your relationship with them. All of us will be treading lightly throughout the holiday season with in laws.
Is there another W in the picture? I know this can be a painful question, but you need to determine that. If not then there are certain ways to progress. If so, then you need to begin hunting down posts that discuss OW with EAs and PAs. These can help greatly. So just keep that in mind.
As far as him taking notice of your willingness to change, that is something that takes much time. Many of us have been at this a while now and our respective spouses still don't acknowledge the changes they see. Remember, they are for you and your children. IF they benefit him, then OK. But first and foremost they are for you. In my case I lost 25 lbs in about a month. My W mentioned it this morning - 5 months later. Don't dispair, start working on the things mentioned by TrentC and anything else you know you need to change FOR YOU. Although no one here can determine the outcome of your sitch, everyone can tell you that by doing 180's and improving yourself you WILL feel much better about yourself. Your H is in a FOG. Dont forget that.
There has been much ring discussion as well thought the boards. This one tends to be a personal preference. For example, I didn't wear mine except for business trips during most of my marriage. Now, it doesn't come off (unless it falls off because mine is also too big.) My W has decided not to wear hers anymore. So what? That is an issue for her, not me. So don't worry about your H. That is one of those things that can only end in an argument. It's bait. Don't take it. I did and can tell your from experience it is not worth the effort.
Lastly, as you progress, keep a positive attitude about yourself and your actions. Everyone on these boards has made mistakes along the way (I continue to :-)) but, thats the beauty of having this forum. By posting your actions, you can learn from others who will tell you if you did right or wrong - or you can post what you hope to do and figure out before hand if it is going to be good for you and your sitch.
I will keep watching your thread and will keep you and your children in my prayers.
SSGA
ME 41, Her 41 M 18.5 years T 19.5 years s - 12, 10 Bomb 7/12/09 Inhouse Seperation 7/13/09 - 10/1/09 She moved out 10/1/09 - present