I would try and work it out with your Ex. Think it's the best for all concerned. I think OM is mostly just promises.
Think if you opted for him, you would be very sorry in the long-run.
I don't think your Ex wants a marriage like your old one either. If both of you try, I think you can have a much better and stronger marriage.
I think the sexual attraction will come, after you've worked the other things out.
What can you lose from trying your hardest. Either things will work out and you will all be very happy, or you will have the satisfaction of knowing that you gave it your all.
Either way, it will teach your D a valuable lesson.
Not all Exs would give you another try, after you cheated.
Think you are lucky and should give it another try.
Just my opinion...
I'm really sorry about the dog. That must have been very hard!