Jennifer Garner was said to have reached her breaking point with Ben Affleck's drinking and gambling, and that's why she called their their marriage quit.
A Jennifer sources say Ben's drinking and gambling have escalated over the last few years to the point "she couldn't take it anymore, while a Ben sources also say he likes to drink and loves to gamble,in fact Ben has rhapsodized about gambling in interviews.
Sources say "partying" had nothing to do with their problems. Ben did not go out and did not womanize ... Jen complained he just drank and gambled too much.
As for Ben sources, they say it's really just about 2 people who want to live their lives differently.
His people say they've been in therapy for more than 2 years -- he even mentioned his marital problems during his 2013 Oscar acceptance speech.
They add the couple has been separated for 10 months, so there was no recent "breaking point."
TMZ