Jon&Kate plus 8? Sad.?

I've watched the show since Season 1 and have always though of Kate as bossy but I don't understand why people are saying she pushed Jon to cheat??? Also was anyone really sadden by tonights episode? When Alexis asked Jon not leave it broke my heart.Plus he acts like he just really wants out of the responsibilty of being a husband and dad with his needing a break and stuff.