Secrecy, Lies, KISA, Changes in behavior re exercise, clothes, appearance
@ilikemycofistrong, in my view your H is still duping you. He is clearly infatuated with this young woman and his latest ‘Oh I wasn’t aware’ routine is further manipulation to throw you off the scent, just as his ‘I see her as a daughter’ was. He is making a mockery of you and massively disrespecting your marriage and family.
He fancies her and is buzzed by her attention and validation. Key is what she/their dynamic symbolize to him about himself. Perhaps he is trying to reconnect to his younger self or create a new adventure with a younger woman. He is lapping up having her in his car, being her confidante and advisor, and partying with her and her friends. He’ll be thinking of her while being with you and your son at home.
Have you investigated his phone to check if they are messaging? It is undetermined if this is one-sided, a mutual flirtation, an emotional affair, or more, but it does appear that she is entertaining and enjoying his big crush at the moment. Their colleagues and her friends will have clocked the panting Rescuer and his Damsel.
He is playing with fire and jeopardizing his personal and professional lives for ego thrills. In your shoes I would say, ‘This stops now’ followed by the consequences which will ensue if he balks at: only distanced professional contact with OW, no more lifts, no more advising, no more nights out when she is present. Plus IC to examine his character flaws that enabled his inappropriate behavior.
I must say, if my H had employed subterfuge about an OW at work and had been invested in promoting, protecting and escalating their relationship, he would be leaving to give me space and changing jobs, and even then I would seriously consider divorce. The problem here is that your H is deep in the fog, so he will likely take things further underground. Expect denials, downplaying, blocked transparency, and gaslighting.