Mary J. Blige's estranged husband is demanding a 6-figure check from her ... EVERY month, while they hash out their divorce.
Martin Isaacs filed for temporary spousal support, and according to the docs -- obtained by TMZ -- he thinks $129,319 per month is a nice, round number. His argument is simple -- Mary was the breadwinner during their 12-year marriage and got him used to their lavish lifestyle.
Martin says Mary earned anywhere from $1.5 to $5.1 million over the last 2 years. Remember, he used to be her manager ... and he points out she's currently on tour with an album about to drop. He, on the other hand, has zero income since Mary fired him shortly after she filed for divorce.
As for that prenup we told you about ... Martin believes it's bogus since he signed it without a lawyer. And he says Mary knows the prenup's BS, as evidenced by the fact she's already cut him 2 checks for a total of $85k.