Worried I’ve messed up the best relationship I’ve ever had

Me (26) and my girlfriend (25) have been dating for almost two years now and it has been the best I’ve ever had, we’ve had no arguments and it’s been perfect.

One day I saw her private Reddit username while she was showing me a post and I ignored it for a while and thought nothing of it. She has shown me posts on it before but has expressed it is private. One night obsessiveness and curiosity got the better of me and I looked it up and saw a few private posts, clearly personal but nothing I didn’t already know I think, I closed it and felt awful, it was a private Reddit and though I don’t think I looked at anything too deep, I know there are some really private things on there, almost like a diary. I still broke her trust and invaded her privacy.

I have since confessed to her after a few weeks of living together and though she was (rightfully) really upset but she said she still loves and forgives me, though unsure if this is just because it came out of the blue and she’s not process it (we’ve not had much time apart) i told her this less than 2 months before our exams too, perhaps just to ease my guilty conscious and worried I may do it again, though I thought honesty was the best policy, I’m now thinking I should have kept it private for the sake of the relationship. I am struggling to forgive myself and have been acting horribly like a man baby since telling her too (she says it’s all fine), I can tell she is becoming distant, likely due to my behaviour. our lives are intertwined with work and friends so must be difficult for her to initiate a breakup if she wanted to but I love her so so much and my guilt is making me crazy and depressed (though obviously i have no right to be as I’m the one who fucked up ). She still wants to have sex but I’ve turned her away saying that I don’t feel like a deserve it after what I’ve done, feel like she needs to be angry or I need to be punished or something. I fear I have ruined her trust in men as a whole and ruined her life as a result. What can I do (if anything) to help this situation or is it too far gone to save, what can I do to make her life better, I have since started therapy as no one in a sound mind would do that to someone they love, this still doesn’t help my gf who I have hurt and feel I am now emotionally manipulating.
I also feel like I have taken away a private forum from her now that I have told her I have seen it

TDLR- saw my partners private Reddit username, looked it up one day then confessed a few weeks later, says she forgives me but I can’t seem to forgive myself and have been acting horribly- making things worse. our lives are intertwined and before this is was the best relationship either of us have had. is the relationship salvageable or is the damage done?