Mike and Emily cheating affair

I don't think I've seen it brought up, but I've been thinking about the Mike and Emily cheating story line, we know Emily did sleep with Mike (assuming she's just saying what Matt wants to hear) but we don't know when, or if Mike dating Jess or if he knew about Emily and Matt. I've kind of assumed that Mike didn't want to go on with anything anymore and that's what we see in the telescope.