Bottom line it wasn’t a great idea to chat to her very attractive, leggy friend for so long, so soon after you met them both. No matter how non-flirtatious it was, it was always going to get back to your girl and arouse suspicion, and you dug a MASSIVE hole for yourself. Some areas should just be avoided.

If it was a non-flirtatious conversation, maybe explain to the personal trainer girl the misunderstanding that has happened and how pissed of you are, and ask her to explain the real situation to your girl and get you out of dodge.