Sources close to Tamar tell TMZ ... the singer's marriage to estranged hubby Vince Herbert suffered an irreparable fracture after going through a time of depression stemming from her firing in May.
While they're no strangers to a roller coaster of a relationship, we're told losing the gig created bigger issues because it compounded an already teetering relationship. And one of the first steps to get back on track -- moving out 3 months ago, even though they acted like a couple just 2 weeks ago.
Our sources say Tamar and Vince put on an act in NYC as an engaging couple simply to promote their show. At this point, we're told Tamar had already moved in to a baller high-rise.
Her 2-bedroom luxury condo in Bev Hills goes for around $15k a month.