I haven't posted because the question was aimed at single people. I am not single but I know romantic relationships and marriage is definitely not for everyone...
There are lots of happy singles out there as this thread is evidence of and you must absolutely do what you think is right for you.
. However if what you say about you husband is really true ( and I know snippets in a thread here cannot possibly encompass the whole of a life or relationship ) really think what you might feel 2-3 years after the divorce when your husband is with someone else, who your children may have to spend lots of time with, Someone you have no say over.
I am not saying to stay with your husband just for the children , I don't know your life and if you really cant forgive then you can't. You H was definitelya twat.. I am however willing to bet he will be in a relationship very quickly after you divorce. Especially if he really is handsome, kind, a good father and was just an idiot once a few years ago when you were having a rough time.
If that scenario of your husband happy with someone else.and you having to accept that oerson involved in your childrens lives genuinely feeels OK with you, then fine.
Just spend some time thinking about how that will feel and how it will affect your life before getting a divorce.
I am not saying that your marriage can survive what he did but in the situation you have outlined, I'd want to be very very certain it couldn't survive ( even if it was changed) before divorcing, particularly if I had young children.
Listen to what many of the single people str saying. They don't want the work of a relationship and that is a perfectly valid choice. All long term relationships require work, effort and compromise of some sort. Absolutely all of them. In good ones the work should be done by both parties, mostly feel good, even occasionally oyous even if it still take effort. Occasionally ( and it really should not be very often if the relationship is to be a good one) the work is messy and painful
Good luck, whatever you decide .