Don't worry too much about it....it's just words...
My boyfriend was talking to another girl, and when she texted him "hey" he responded with "hey beautiful"… is that considered cheating? I don't want to say anything because this is a new relationship but.. I don't want to let it be either!
I would keep an eye out. That sounds like straight out flirting, and if its a new relationship and he's already looking around elsewhere I'm pretty sure you guys won't last. Sorry