I took a look at their charts when I heard this news. This couple has been married for 40 years, so not an easy decision. Al's moon is getting a direct hit from the transiting cardinal cross, with Pluto on his moon, along with the June 26 lunar eclipse. When Uranus went into the world degree of Aries, it directly squared his moon and they decided to make a public announcement. The moon rules our feelings and close family ties, which undergo drastic changes when impacted by these transits. There was also a news report about another house being purchased -- another lunar reference.
This separation was probably in the works for awhile, as Pluto had opposed Tipper's Uranus back in November 2008. There might have been incidents back then that led to this decision. Pluto is also favorably aspecting her Mercury in Virgo, which has likely led her in a new and more fruitful direction. Perhaps she will write a book.
Watch for more of these sudden unexpected decisions with well-known figures over the next few months.