<human>: Can you succinctly summarize the text in 1-3 sentences?

M26 and girlfriend F23 have been dating for 9 months, the relationship is going very well and we're both happy together after getting out of previous relationships right around the same time.

We got in a small argument a couple weeks ago, it blew over quick and we both apologized (although she admitted she was being ridiculous). Right after that her old co-worker (M probably 24-26) started "liking" some of her facebook posts. I think nothing of it but am a little suspicious. I feel kinda crappy but I caught a glimpse of her texts and noticed his name, I've waited a bit but curiosity got the best of me and decided to check it out the other night. 

Her text was to him about a month ago, saying she misses him, had a dream they went hiking and she wanted to get together for drinks. His reply to everything was pretty much one word answers "LOL" "yeah sure" thats about it. 

Feeling a little weird about it I checked her fb, all messages from him were deleted except her last reply. What's weird about that is she doesn't delete anything else, just those ones.

Am I overreacting to this? I feel bad I violated her trust and checked out the messages...but at the same time I'm concerned about this guy. I don't mind her having male friends, I just don't like her contacting him behind my back. What to do?
<bot>: Sneaked my gf's texts, noticed she was talking to an old co-worker but unsure if it's a big deal or not. Feel weird about the situation.