Gwen Stefani: Blake Shelton Has Done Wonders for My Self Esteem

Gwen Stefani was attracted to Blake Shelton like a magnet, because he resurrected her self-esteem ... so say some of her closest friends and associates.

Gwen told people in her life, Gavin Rossdale was a "control freak" who said disparaging things to keep the upper hand in the relationship. Our sources say Gwen complained Gavin had an issue with her parenting skills and criticized her for not being a supportive wife.

Gwen, we're told, was "blown away" by the kindness Blake showed her after she split with Gavin. "It made her feel good again," said one source. Blake also won her over by just being fun ... something Gwen said she had been missing in her life for a long time.

For his part, we're told Blake called Christina Aguilera last week -- before he hooked up with Gwen -- and told Christina he had "a crush" on Stefani. Christina's response offered little hope ... "Ha, good luck with that." Turns out Christina underestimated him.