Personally I wouldn't be able NOT to say something, it would eat away at me and I would need to discuss it with my husband and try to find out why he stinks of another woman. Of course there could be another explanation (not sure what!) I think everyone is different and would handle this situation differently.
I take it your talking about a female partner, it depends on whether you want to carry on burying your head in the sand and be with someone who may not be being faithful to you.
It will fester if left alone.