i know she wouldn’t cheat, that’s one thing that attracted me to her was her loyalty.
Would she consider it cheating if she's already said she wants a divorce and the marriage can't be fixed, she's cut off affection, and she's spending her evenings away? You say she's Snapchatting other men. You know her better than us, but from the few bits you shared, that doesn't sound far away.
I'm sorry you're in a difficult situation. I hope you find the patience to persevere and be a better you.