So do I tell him? ?

So my wife has a sister who is dating a new guy. Of course she tells my wife all the details including the sex which of course my wife tells me. The sister's main complaint about the new boyfriend is that he doesn't have sex with her enough and she is considering having an affair with another guy to get her needs met. I feel like I should mind my own business but bro code tells me that I should tell him. What should I do?

So do I tell him? ?
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