You’re not wrong to feel hurt or suspicious what you found would upset anyone. Deleted messages, sexual texts, and time spent alone with this coworker cross emotional boundaries, even if she insists nothing physical happened.
Her reaction turning it back on you for checking her phone suggests defensiveness instead of empathy. Trust can’t survive secrecy. If she values your relationship, she should be willing to answer questions honestly and rebuild that trust through openness, not accusations.
Ask yourself whether her words and actions match. If she continues to hide communication or spend private time with him, she’s showing you where her priorities are. You deserve honesty and respect, not uncertainty and guilt for caring.
If she’s willing to be transparent and set boundaries, you can slowly rebuild. But if she won’t, protect your peace and consider moving on. Trust once broken can be repaired — but only if both people are willing to do the work.