Both men and women have built in ways of identifying a mate. For men, it seems like the visual is a much higher priority than for women. Most men are naturally going to identify an attractive woman, and want to look. This is completely normal in my opinion.
It's funny you bring this up today actually, because I was just noticing this effect yesterday. I was at the gym, playing a game with about 5-7 other males. An attractive woman started working out on a machine near buy that was visible to everyone in the room if they looked in that direction. Yes I looked. But I was also careful to pay attention to the others to see how many of them looked. All of the adult males appeared to have a difficult time not looking. I noticed that each one looked several times.
The point I'm making is it's normal for men, and your husband to want to look. I don't think thats the real issue. The issue as I see it is two fold:
1. He was evasive and dishonest when you asked about it. This kind of dishonesty is the type my wife practices a lot as well (she is getting better though). She will say something that is technically true, but not honest. This is mostly the way she lied to me during her affair. "I am going to see my AP to drop some legal papers off" - technically true. She was dropping papers off. But then they wen't on a date, and had sex as well - the lie by omission.
Yes it's true he was looking around the room. So in his mind I'm sure he feels like he was being "honest". But the real truth is he was checking an attractive woman out. I think your brain subconsciously understands this kind of dishonestly, and given what he has done, it causes you to feel unsafe emotionally. This is expected and I don't think anything is wrong with you.
2. I'm guessing that an attractive woman makes you feel uncomfortable for the same reason my wife being nice to an attractive man makes me feel uncomfortable. We are not fully convinced that they have changed their ways, and that they are going to be able to resist temptation this time around. We now know their weakness, and what they are capable of, and don't want to feel the pain of betrayal again. It's probably our body's defense mechanism kicking in trying to defend us from the pain we experienced in the past.
It would be like a former alcoholic picking up a drink menu. It's scary because looking at the menu could indicate they are thinking of having another drink, and starting the addiction up again.
Of course this is going to make you feel unsafe. I don't blame you or think you are being unreasonable. His actions caused deep wounds in you. It's expected that you might bleed on him a bit while he's trying to help you recover. He needs to understand and be okay with this.
I don't know how someone who is "reconciled" would react to this type of situation. Maybe thats what being reconciled means. That you don't have a reaction like this when a similar situation comes up. I don't know.