> I don't see how sleeping with someone has any impact on the company. We don't even know what arrangements him and his wife may have. But in the worst case, it's immoral and wrong but a personal issue for him and his family.

Yeah, if it's just some rando at a bar, then yeah it's primarily an issue for the family. (besides the fact that it indicates honesty issues)

Sleeping with a spy is a direct threat to the company. The spy isn't sleeping with him because she likes him. She is literally doing her job, which is to compromise the company. The issue is not the sleeping around part. The issue is the spy being brought into the company part.