I'm so sorry you're hurting, zoie.
Sometimes it takes a long time to discover that the person we thought was perfect......isn't.
I understand how it feels to have such a strong partnership and then have something happen that cracks it. It's a sick, sad feeling.
Is there a way, when the dust settles a bit, for you two to go in for counseling together? If you wanted to? At least you would know if there's any possibility of having back what you (thought you) had before.
Hugs to you