When they are alone Michael should confess his drunken night of sex after he saw video of Drew and Willow having sex ... BUT I can also see him not telling Willow who he had sex with.
Michael owes Willow the truth about what he did, but nothing is served by naming Sasha.
Both of them had their lives blow up, got drunk and ended up in bed. Not a good thing and Michael should confess to Willow and Sasha may be in a relationship or situation where she needs to tell someone the truth.
Of course this being a soap the truth will come out at the worst possible time -- but for now I'm ok with Michael keeping mum about Sasha being his partner in pity/anger sex.
Karen L.