WCW, I believe that you should be honest with H. Tell him, I have "chosen" to forgive you. This is a work in progress for me and I anticipate set backs, but I am determined to work through this and I would ask that you be patient with me. It is a journey and I want to go on this journey hand in hand with you. And then, you have to do the work. Personally, I have good days and I have bad days but the good is finally outweighing the bad and it will for you as well.
Pregnant, I understand that your in laws hurt you but to be in touch with you and your H while you were separated would have put them in the middle. Do you know if they supported your H's decision? Did they say that or are you assuming it? Why don't you just tell them that they hurt you through this but because they are your children's grandparent's you are willing to put this pain aside so that they can have a good relationship with their grandkids. Your R with them is immaterial. You only need to be cordial. Remember when you forgive someone it doesn't mean that you have to jump right into that R. You are free to never have a R with that person again. But you MUST NOT hold the offense against them. My advise is to you that friends come and go but family will always be family and I believe that you need to work on that.