MillyMollyMoo, I'm truly sorry to hear how your husband is treating you. You say you have children which makes me thinke he's not a teenager which should make him stomach not going out all the time. Some men just think their entitled. I'm also sorry to say that given the back story (I read the previous thread, thanks to the link) and can't think he hasn't had an affair. I can't think why you should degrade yourself to be in the same room as someone who thinks nothing of fucking your husband while your 7 months pregnant. The fact that you might be in the same social situation tells me she knows full well that you are pregnant plus has other children. Perhaps you should either do as PfftTheMagicDragon says and tell him you know and that he has a responsibility to ensure your marriage survives, or confront her (even just ask her what she's up to, it might shame her sufficiently.
If, as you say, your aware of his faults and your biding your time then please please please make sure you bide it properly. Devious as it may be tell him household bills have rise and tuck away the money - trust me you'll need it before you get any maintenance or child support or whatever. Also make sure you've got the legals sorted, like who owns what part of the house, who's name its in etc etc. AND, work damn hard on your degree. If the day comes and he leaves or you can't take it anymore then you, and your children, will need you to be able to support them. So focus all your energy on your children and your studies. That is what counts, your husband does not. Obviously he might be a lovely dad and a decent husband at times but make no mistake a man who's decided to leave the home or has been kicked out for bad behaviour wont be keen to cash out for his family later - and he'll be thinking of himself (partying, setting up a new home) thereafter. So put aside all the money you can and get your degree. Be glad you have had your warnings, there are women who dont.
To all of you who now think that I hate men, I don't. But I have seen friends who have been left destitute by unfaithful men so would like to pass on advise they would give.
I'm not saying, MillyMollyMoo, that you shouldn't try to work on your marriage or whatever and I wish you all the best for the future - just look after yourself and the little ones.