Johnny Depp and Amber Heard's relationship was extremely bitter due to a full-blown feud between his family and Amber ... and this, we're told, is the backdrop for what is already an acrimonious divorce.



Multiple sources connected to the ex-couple tell us, Johnny's 2 teenage kids, his 2 sisters and his mom "hated" Amber, and openly discussed it.  We're told they talked about how Amber would rail on Johnny and "treat him like crap."
Earlier this year, Johnny moved his mother, Betty Sue Palmer, into the L.A. compound where he and Amber lived ... and the tension was palpable. We're told mom often told friends she thought Amber was using Johnny for his money and fame, and to boost her own career.
We're also told before Betty Sue moved in, she only saw her son once from the time he married Amber, and both Betty Sue and Johnny blame her for keeping them apart so she'd have full control.
Our sources say Amber had 2 closed door sit-downs with Johnny's mom after she moved in, and after both meetings Betty Sue railed on her daughter-in-law, calling her a "terrible person."       

We broke the story ..Amber filed for divorce Monday .. 3 days after Betty Sue died. There was no prenup, and Amber wants spousal support.