Right to be concerned?

Almost 10 months post DDay. WH had a 6-8 week affair with a woman he met online. I won't get into details. He ended it on DDay and R has been going fairly well overall and WH has been very dedicated to learning about himself and rebuilding our marriage. I'd say I have been doing exponentially better in recent weeks and triggers have fewer and fewer. Until yesterday.I dont visit his office often, because I work full-time, and I suppose I hadn't give much thought to his female coworkers, since the AP was a complete stranger to me.

Our kids and I popped by my WH's office yesterday afternoon because they had a dentist appt down that direction. He'd invited us, so it wasn't an unannounced visit. When we arrived, his assistant was in his office, sitting casually on the couch. When the kids and I entered, she continued to sit on the couch while the kids and I chatted with my husband and made not effort to leave. I felt a little awkward, but didn't think too much of it, until I was driving home. It struck me that my husband had been talling me recently that this assistant had been telling him about her relationship woes with her fiance. I'd say they have a fairly social office culture, and he tells me about his coworkers often.

Anyway, I was extremely triggered by this interaction and shared that with my WH. While he assured me he is very aware of boundaries with the opposite sex and stays professional at work, I don't trust other people. His AP very clearly took advantage of his "nice guy" persona and appealed to his "helper/fixer" nature. We're 10 months out, but he hasn't necessarily dug too much into that part of himself yet.

I guess I'm just looking for validation on my being triggered....anyone else? How did you approach it?