DMX will be working on his issues … the marital kind … on VH1’s upcoming “Relationship Rehab” … TMZ has learned.  The troubled rapper and his estranged wife Tashera Simmons have agreed to appear on the upcoming reality show in the hopes of getting their failed marriage back on track, a source close to production tells us.

The couple separated in July 2010 after 20 years together, but with four kids, they’re not ready to call it quits, yet they are still best friends, insists the source – and that’s why they want to give it another shot. We’re told DMX feels Tashera is “one of the only people [he] truly ever loved and has been down with him through thick and thin.”

The show is called “Relationship Rehab” and will address the six children DMX fathered during their marriage.