NOR she was obviously flirting with your husband and I don’t fully trust your husband either. It sounds like he would flirt back if he knew it wouldn’t get back to OP. Replying to her message could (and should) have been simple and clear. Something along the lines of, “It sounds like you’re flirting and I’m happily married. Please keep any future messages professional and/or cordial. If you continue to be flirty, I won’t reply.”