What should this be considered?

I woke up this am and finding my husband texting one of his female friends. I was being curious so I went upstairs and I checked the iPad since his fb messenger synced from his cell phone. I read the convo. What it says was how lonely she was feeling and that she bought a lingerie blah blah. His reply was oh good thing you're spending money boosting the economy. I would confront my hubby about it but since he is the kind of person who would do whatever his mind told him. I just played it cool as I'm unaware of anything. My thinking is that to keep it on the down low since there is nothing sexual and the fact that he didn't care much about it.