Matthew Stafford's wife, Kelly, is issuing a mea culpa ... saying she's truly sorry for calling an Instagram troll a "misogynistic pig" after he criticized her for not wearing makeup.
The troll left his rude comment under a photo of Kelly and her kids ... saying, "[Matthew] could have his pick of women so just a little bit of makeup."
"If you weren't married you'd have it on."
Kelly was so pissed about the hurtful words .