I am so sorry that things are so hard. Good for you for being an adult in the sitch. I am one of the people who frequently comment that D is no piece of cake but I will concede this: If it happens, despite what you know to be your best efforts, in time, there will be a certain measure of peace. I KNOW that D was the right thing in my sitch. I didn't 100% know that at the time. It was excruciating and misearable and I ached for my children (and sometimes still do since their Dad has become sort of a dropout as a Dad in addition to being a financial deadbeat) but they are doing exceedingly well. If there is ever a time when the reality of a "broken home" hurts them too much or causes a decline in their overall ability to function or their ability to cope I will get them the help that they need. I never badmouth their Dad and I don't list the "reasons" for the divorce - I simply tell them that we had some problems which we tired to overcome together but were unable to. They would like more info sometimes but it would do them no service whatsoever.
Fran, my ultimate point is, do not allow fear of the unknown to prevent you from doing what you must to make this marriage really work or to be done with it. You are a good person and deserve much better.