If a man single or married has erectile dysfunction then unless he is on medication such as 'Viagra' then he wouldn't be able to 'get it up' so an affair would not likely happen unless on medication. If the man is on medication and resolved his problem he may feel frisky and feel he needs to prove his manhood by having an array of women or at least one woman in his life. Not all men cheat on their wives just because they have erectile dysfunction.