Should I tell the wife?

I'm 23 and i work in private practice as speech language pathologist. My mum is my boss. I have been having this kid for about a half a year, nice parents, bring gifts to celebrate small achievements like any other so didnt think much. Today his dad came and gave me 10 euros extra "for coffee" and i tried to refuse but he didnt accept no. Then he tells me he thinks im really cute. And im like hahah thanks? Then he continues with "dont tell my wife" and im like hahahahah yeeeeaaahh. Then he tells me to call him if i ever feel lonely. And im like hahahaha??? He gets to door and asks me "so when are we seeing each other?" And i just answer with the appointment date/time i gave to the child. And he just kinda stares as me. Then he asks if im single. And i say no. Then he just says "okay then we wont do anything i guess" and leaves. I already told my boss(mum) and she told me not to tell wife and keep it professional or she'll fire me and with situation in my country i cant get another job yet so i figured ill tell the wife in a few months when i get another job. But a lot of people around me tell me not to say anything because its not my bussiess and its their private life. Im lost as what to do. If I was the wife, id like to know. But i dont want to cause problems for them or myself.