<human>: Can you summarize the given text in a few sentences?

This is my first long term relationship, and it has been great. Last month we talked about how hard it is not seeing each other that often (due to University), but thats the only sign of unhappinesses over the whole period we've been together. She slept with a guy she doesn't know on a night out where she got really drunk. She says she is so sorry and will do anything to carry on the relationship. We have never had any issues with trust, even in University. One part of me wants to believe its a terrible blip, the other half of me believes if she did it once, she'll do it again and the intention to cheat must have been there to begin with (even if shes "isn't the type"). She's given me full control of her phone and social media to prove that her story is correct (which I believe) and offers to keep it that way if I wanted gain trust back. Any advice would be appreciated as I've never had to deal with anything like this before.
<bot>: Girlfriend of 2.5 years had a drunk one night stand and will do anything to make it right. Thoughts?