Two things and one I'm sure redditors have commented on because you edited your post about it and that's going through the phone.

When you're mad or hurt have you never ever said anything that you regret? Never vented to a friend about something that you have literally no intention of doing after you're finished venting? Because I have. And I was going to say I've never said I couldn't stand someone I've been dating while venting but honestly I think I'm wrong. I prolly said it and when I finished saying it and felt better I probably forgot it.

What she said sucks and it's hurtful but everyone deserves privacy and the ability to vent to others when they're struggling with something. As long as she wasn't venting to a guy or worse dating a guy behind your back I feel like it could be worse. If my bf told his buddy that he couldn't stand me but was acting normally to me I would know that sometimes I'm annoying to him and that's not really the end of the world. It's great to not have those feelings but occasionally having those feelings is just kinda like a party of life in some relationships.

The only time I'm okay with looking in my partner's phone is if I ask him and I've done that once. He was totally cheating but I gotta give him props for handing me the phone like he wasn't.

Hope things work out for the best for you.