OP what an awful, awful thing to have happened to you. Especially being pregnant and right before xmas.
I am in awe of how brave and dignified you sound. Don't worry about the silly DM picking it up. You come off very well. Your husband does not (more concerned about himself rather than the effect on a very pregnant woman or a small child).
Beware of the hormones after giving birth which will make you so sad for the 'father' not to be there to see his child (although he is clearly not too bothered about them). As you say it is your security and faith that has been shattered and that is going to take a while to come to terms with.
I had someone cheat on me once (that I know about). I tried to stay and ignore it but it ruined the relationship. I felt betrayed, hurt, angry and humiliated. I could also never trust him again and drove myself mad wondering where he was, what he was up to constantly. Any peace I had was gone. Although it was heartbreaking to be out of the relationship and so sad at the loss of what could have been great, there was no putting the genie back in the bottle.
I agree with the poster who said be careful what you post here re legal actions you take etc. You definately don't want him or the other woman to get info like that. It does sound like you are very sensible though and have lots of family support which is brillant.
Sadly based on his behaviour it does seem he is only concerned with the inconvenience to himself rather than upset at what he has done. It is always very painful when you have to face up to a new harsh reality but you sound very strong indeed.
Your thread although a sad topic has been quite inspiring for the way you speak and are handling it.