My boyfriend cheated with his ex

I just found videos in my boyfriend’s phone of him having sex with his ex. It’s happened multiple times throughout our relationship. I’m sick to my stomach. I know this is unforgivable and I just don’t know how to feel from here. I am in shock I haven’t even cried yet. I just need some support woman to woman. How did you heal? Please tell me this pain won’t last forever. I feel like I’ll never trust anyone again.