Should I be worried about messages/dates or am I paranoid?

Dear all - would love to get your view on the following: I was reading on my wife's phone as mine was charging and spotted by coincidence that my wife has been receiving and sending multiple messages from her old boss (50ish, my wife is 20y younger) for multiple dates mostly for lunch, sometimes for an industry ball or drinks where she reaches out herself to him stating 'I would love to see you again'. When planned meetings with others got cancelled, she reached out to explicitly ask for her lunch with him one on one to be reschedule and afterwards her ex boss sent her the following quote: 'Great to see you 4 lunch. Highlight of the day. Shiny'. He did not miss to send her a birthday note for any of the last 4 years all along the lines of 'welcome in birthday land - wishing you the shiniest of days, shine on!'. When meeting him for lunch he sent texts like 'Jef: Downstairs - Mint Bar.
Shiny' to clarify where he is - I don't think 'shiny' sounds professional vs flirtatious to me but when I confronted her with this topic, she said she would regularly every 3 months or so meet him for career advice and it was laughable that I would be worried about her with an old man. When reading another thread with her friends on Whatsapp as I got worried I looked further she stated she likes old American man. She tells me I am crazy and paranoid - I felt my reaction was normal and had a heated debate with her at 2 am in the morning as I couldn't sleep but apologised afterwards to her for calling her behaviour cheap to flirt with older man that way even if it was nothing serious. She called me paranoid and called my behaviour abusive and controlling. Let me know please how you would feel about finding such messages as well as other messages from work related men at 3-4 am in the morning asking where she was to join 2 infamous late night clubs. Forgot to add whenever my wife reached out and her ex boss was travelling she always followed up with quoted like 'well hopefully see you soon - maybe lunch' when he could not make drinks. Found another male ex colleague sending her a note at 1 am in the night 'How are you? Believe it or not, I am in (nightclub XYZ) and can see up to the balcony at Crystal- memories of 2009!!'. Am I paranoid or is it normal to be worried or not excited about this?