His private life is irrelevant. He’s an adult and can do what he wants. It only matters if he spilled secrets to the spy
its not really about his private life its about whteher he was manipulated into it wihtout his knowledge. Psychological manipulation is a thing and if they got him to do this what else happened?
https://foxandlion.pub/analysis/traitors-among-us-who-is-vul...
> A balanced, patient, and motivated Machiavellian can wait while they cultivate what they need. They may take 10 years to act; they may well wait 20 years. When the strike comes, it will come out of the blue – and their tracks will already be covered.
It's obviously not irrelevant for two reasons, one practical one moral. The practical one is that you don't need to 'spill' secrets to a spy. Having one around you in private means you can be bugged, blackmailed, have your means of communication compromised and so on. It makes you vulnerable by definition.
Secondly if he's willing to lie to his wife and family he's obviously willing to lie to anyone for much less. It tells you something about the character of a person, how can anyone trust a cheater?