Understood, but it's her he's besotted with, her credited with his image revamp, her he's listening to. She has power over him, they don't.
Anyway the stakes are higher now, plus she is news not history- future PM Johnson discusses with her not them and privately he can't be 100% sure she's fully committed nor what her longterm ambitions are. The consort of the leader always has power within the court and a voice (spoken, attributed to a source or background briefed) that can extend much further than someone who spilt beans years ago. Whatever media access previous women in his life have, she outranks them as a former Conservative party communications chief who was named as the UK’s second most powerful public relations professional by PR Week magazine.
And she was intimately involved at CCHQ during the fake news/Cambridge Analytica campaigns around the referendum and GE, so must know her way around the dark arts and where a good few bodies are buried.
If he organises his life such that his relationships break up with grudges he's walking on eggshells.