The STI thing is tricky, so safer sex all-round, I'd say, unless he is willing to get tested here and share the results, but even then, how do you know what other sexual relations he has on his travel?
The thing that bothers me is the thing about his wife - he says they are separated - how do you verify that in any way? He may be a happily married guy in Brazil with kids, and he is looking to set up a relationship for himself when he makes his frequent trips to NYC. that's definitely not unheard-of. The question if, how much you care about that, I suppose.
Please check out The Birdcage - an open, friendly Polyamory forum for all parts of New York State
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