<human>: We knew each other somewhat in high school and then matched on tinder and talked consistently for about 3 weeks or so. I had a party at my house last weekend and he came over and it was fine, and then he asked me out for drinks this weekend. 

Last night we meet at the bar and it was good. The bar closed so we decided to move to another one nearby and as we were sitting in his car I noticed a text from his ex girlfriend [f20] come up on his phone. I played it cool and just acted like I hadn't seen it, but I sort of freaked out. They were together for 3 years and just broke up around January. She has a boyfriend that she's been seeing since December or something like that. I never saw the actual text and it was just her name that came up, but why would she be texting him? And at midnight? 

My friends say this is a major red flag and that I should run for the hills. Sort of disappointing because I thought the date went really well. Thoughts?

Provide a brief overview of the text.
<bot>: went on first actual date and saw a text from his ex girlfriend pop up on his phone. Friends think I should cut him off.