Al and Tipper are ending their 40 year marriage. Maybe he got tired of saying "Tipper"? I predict she got more religious, and/or he found some young hippie green woman who swoons over his ozone PowerPoints.
Something happened, even though they said they "grew apart". Why else can't they just sleep in separate bedrooms like normal people in their 40th year of marriage?
I might be right about this. Expect Al to have a new girlfriend soon.