Mrscraig so sorry for your pain.
In my very humble opinion, as someone who has not been in this situation, I think in the long run it is a question of whether you want to stay with him and him with you, if the answer is yes then can you forgive him and can you trust him?
I hope you will work out what is best for you.
The other woman has caused you immense pain, yet I feel that it is your husband you are really mad at, and yet as you love him you cannot fully blame him. He is to blame but he can be forgiven.
If you choose to forgive him, it is something that will take time. I do not speak from experience so maybe I should not say, but I have seen the result of not being able to forgive or trust in a relationship after unfaithfulness, and that is corrosive.
I have also seen the turmoil of someone who wanted her husband back but he did not want to come back. If you want him back and he wants to stay with you, can you rebuilt your life together? Only you two know if you can rebuilt. Maybe it will not be the same, maybe it will be different. But will it be better or worse than being with someone else or being alone.? Again, only you know.
So if you do stay together please find some way to forgive and move on for your own sanity, and if you do part ways, equally please forgive and move on. What he has done is very very hurtful, but he did not do it to hurt you. So many men in the world (and some women) purposely hurt those closest to themselves. So even if there is nothing else good you can find in your heart at the moment it was maybe a very foolish mistake and not a deliberate act. But I don't know the circumstances so all I can really say is wishing you all the best for your future whatever it holds.