Op,
Don't even respond. No response is a response. Just go radio silent. It will be very telling to see how hard (if) he tries to stay in contact with you. My feeling is he will slither away. Treat his behaviour with the contempt it deserves.
If you feel the need to send a text and he is as vain as you said, and feel like head fucking him a bit, maybe something like
'After some consideration I think this has run its course. I'm on track for promotion and need to focus on that, you need to focus on your narcissistic tendencies with a therapist/ exorcist/dog trainer, the stars just aren't aligning.
Also, someone when we were last out together, mistook you for my Dad. I didn't mind the age gap, when it was just your immaturity, but I don't want to give the impression I have daddy issues. I've now blocked your number. All the best'.
FWIW, I think he's considering early retirement, which is maybe 10 or so years away and wants to make sure you have the income to support his lifestyle, and a nanny as he won't lift a finger with any children. I also wouldn't be surprised if he has debts, secret kids or something dark under the surface as keeping you away from his friends is massively suss when you could easily track them down on social media.
I want you to do something for me OP. I want you to sit and list all of the things about you, that make you an absolute catch. All of the positives. Everything you like about yourself right down to the tiniest little thing. Add to it over the next few days. Re read it. Memorise it almost. So whenever you have a wobble about this so called man, or a specimen like him, you can wear it like amour. You are an Hermes handbag and he's treating you like a tesco bag for life. That doesn't lessen your value, it makes him an idiot.
Consider the year you spent with him charity work helping the less fortunate and go back to being your high achieving, considerate, fabulous self.
If you need your crown straightening, let me know. When women build other women up, amazing things happen!