A few things I picked up from Wikipedia and IMDB...
Bill Murray was married when he started an adulterous relationship with his second wife, who divorced him this past June.
He married his first wife when he was 30, during the filming of Stripes, in 1981. I don't know how old she was. They had two sons. They filed for divorce in 1994, because of the affair. The divorce became final some time in 1996.
The second wife had 3 sons with Murray before they were married; the birthdays are January 11, 1993, October 6, 1995, and January 27, 1997. They were married July 4, 1997. They had a fourth son, born May 30, 2001.
The second wife's birthday is May 11, 1966. She's almost 16 years younger than Bill Murray. Based on the date of birth of their first child together, it's very safe to assume that they started their (adulterous) relationship before her 26th birthday. She was a costumer on Scrooged (1988), Ghostbusters II (1989), and What About Bob? (1991). For that last film her credit on IMDB is costumer: Mr. Murray. So they met when she was 21 and he was 37, assuming that the filming for Scrooged happened in 1987.
I'm not saying that these facts paint a flattering picture of the guy, but it's not like his attraction to young women is anything new. If you backed him any time after Little Shop of Horrors this is the guy you were talking about. The evidence seems to point to somebody who is a terrible spouse and an absentee father. On the other hand, did you buy tickets to The Life Aquatic based on the actors' personal integrity? Is it that hard to believe that someone who has spent decades as an out sized comedic actor might not be as grounded as your uncle, the bank branch manager?
If you ask me, the guy who made the comment to him that he's "making bad life choices" is the dick in that Page Six article. What does that judgmental 24 year old chump know? Ever been married? Ever had a rough patch that you couldn't just walk away from with a call to your parents? No? Huh... that's strange. Drop me a line in 15 years and let me know if any of your self-righteousness has faded. Life throws you curveballs every once in a while, and as you get older it becomes harder to be right all the time.
And really, who wouldn't want Bill Murray to show up at their party? Are you kidding me?