Confused, this is my first time posting in a WS forum.
You're not sure why you don't feel "remorse". You've had yourself an MRI because you know your state mind isn't right with the situation. There have been various labels of personality disorders and codependency discussed as to why you feel or think the way you do. Mid-life as a possibility caught my attention (you describe much of the symptoms similar to it and identify with it) because I think this is a big part of my STBXW's issue, thus I'm drawn to your story. You are at least acknowledging there is a problem and you are trying to understand what it is.
He pretty much does most things around the house which has left me feeling very pathetic over the years. Maybe he's codependent? I'm not sure but we have been talking about that and I've stepped up more and said "let me do that". I feel like the 4th kid here.
That statement tells me that much of your own personal identity has been stripped away over the years. Mid-life can be triggered by this loss of personal identity and an urge to break out and find yourself or your role in life. Done in a healthy way, it's a mid-life transition. In a destructive way, it's a mid-life crisis.
He and I have talked about me dating. I agree it would be better to wait but I know myself and I don't like to be alone so while I can say I will try to be alone I'm not sure how long that will last.
This sticks out to me as well. This should be expored in IC. Why are you afraid of being alone?
I only suggest that the time, energy, and focus is spent researching and reading up on everything you can instead of looking to "explore" single life to find your answers. Other members have given you great suggestions on reading materials. Look into and research the discussed personality disorders. Really invest that time in IC. Do as much as you can to learn about yourself not only for your H or the next relationship you move on to, but mostly for yourself. I think you really owe it to yourself because this isn't cycle you want to repeat if you decide to move on. This should be your personal quest to really dig deep into the "whys" of YOU.
I've read enough stories in mid-life forums that those who do go through "crisis" version (typically lasting anywhere 2 to 7 years) in the end come to the realization of the destruction they laid in their journey to find themselves, go into deep depression and suffer a personal hell of their own unlike any other. Some dig their way out and some never do. We as BS go through own hell in dealing with betrayal but our paths are directed upward and intended with moving on, either in R or D. Us BS will get to our peace in our own ways and at our own pace. But if it is mid-life crisis you think you are going through, you haven't hit rock bottom yet. It would best to know and understand the changes you are going through so that you can manage and cope through the personal voyage of self-rediscovery so that you don't make any more horrible choices along the way. Because if you don't, those horrible choices will be a tonnage of guilt that will hold you down in the hole of depression, thus making it almost insurmountable.
IF it is indeed you are going through midlife-crisis, understand that it is not a reason for your A. That is the difference between a transition and a crisis. The A is destructive act. It's still that action that you fully own. Your husband is willing to work on the marriage then he is willing to help you through your midlife.
Personally, I'm not convinced (yet) that mid-life is what you are going through. I'm not even completely convinced that is what my STBXW is going through. The only one who really knows is the person going through it. There are several stages of it. Research it and see if you identify with it.
If you honestly don't think you can control yourself then you should spare your husband and go forth with D. He and the children can at least start their own healing and acceptance of it.