Bobbi Kristina -- Never Married Nick Gordon ... According to Bobby Brown

Bobbi Kristina was never ever Mrs. Nick Gordon ... at least that's what her father Bobby Brown is claiming.

According to Bobby's attorney ... "Bobbi Kristina is not and has never been married to Nick Gordon." For once, the Houston family agrees with Bobby Brown ... telling TMZ, Gordon and BK never officially wed.

Further, we're told by Houston family sources ... there are no legal documents that would allow Gordon to get any of the Whitney Houston fortune Bobbi Kristina inherited -- if she passes.

The fake marriage revelation flies in the face of several statements Bobbi Kristina and Nick both made on camera back in early 2014.

Shortly after the alleged wedding ... Bobby was visibly shocked when we broke the news to him, and he doubted it was true.