What does Dan sing about in the song "It's Gonna Be Good"? Where is he?

In Act 1, Scene 5, Dan, busy at work, sings an up-tempo song, with the accompaniment of the Voices, about how, in the last two weeks, things have been really good at home and he doesn't have to worry ("It's Gonna Be Good") even though Diana is in manic phase. Natalie refuses to let Henry meet her family, but Dan surprises them, inviting Henry in for dinner.