I should despise her but I can't

Downtime:
Good luck. I can only really echo most of what has been said. It's early days, and people do make mistakes. Unless you are very certain, I would be careful about closing doors at this stage. I believe that affairs are usually a symptom of a relationship that was going wrong, at least from one person's point of view, rather than the whole cause. Relate can definitely be useful, but its use isn't always to get the relationship back together, and may be to allow you to exist better in the future, either for your sakes or for your children's sakes.

My story is pretty long and complicated, but we grew apart and her behaviour became intolerable to live with. I managed to keep my dignity and self respect all through it, and have tried not to be consumed with anger, although I'm now struggling to step out of the "poor me, life is so unfair, I'm such a victim" role. Nevertheless, in the future we will still share children and then, probably, grandchildren, so I've been pretty careful to do nothing to make that future more difficult.

I'm not sure how to advise you to relate at present, particularly in dealing with the children. They will be very in secure at present, and will need lots of reassurance from both of you. They need as little disruption to their routine as possible. Maybe a bit of playing "happy families" in front of them is what needs to be done, but I guess you need to decide what limits you need to set on that when they are not around. And probably you need to be the one to decide on those limits, or you will just be manipulated to suit her needs. It is useful to set boundaries for her (and your?) behaviour and to stick to them.

Good luck, but remember how early it is and don't burn any bridges that you might want in the future.

LLYNBH