<human>: Last night I saw my girlfriend open her text messages, the lowest on the screen was "I love you too x" sent to her male colleague. 

Now I'm not one for snooping, but I can't ignore that. So this morning I looked on her phone, basically she asked him her feelings towards her. He said he hates that she's "the one who probably could have been", to which she responded "I might still be the one". Then he said he was alone in bed, she likewise (bullshit, I would have been with her that night), he replied "don't tempt me, because I will come round". Then the conversation moved to our last holiday with no mention of me, as if she went alone. Then they signed off with "love you".

She finished in the bathroom so I couldn't read the rest. Sounds like an old flame, but this doesn't look good. Now she's gone to work for the day, being in a room, with him. Not feeling great.

We bought a flat together a month ago, so this makes the situation a lot more difficult. I'd also hate breaking up with her as she's usually my rock. What should I do?

Can you summarize the given text in a few sentences?
<bot>: Saw gf confess love for a colleague and interest in restarting things. Just bought a place together, not sure what to do now.