A deaf man convicted of stabbing to death his hearing-impaired girlfriend sobbed Wednesday as a judge sentenced him to 21 years to life, a year more than prosecutors requested, after the victim’s family read heart-wrenching statements asking for justice.

Bismark Lithgow was found guilty in February of butchering Francis Pellerano in her sleep in 2013 and stuffing her corpse into a 55 gallon drum where it festered for days — all because he believed she’d been unfaithful.

“Today we ask you to do justice — to take into account the suffering of this family,” the 19-year-old victim’s great uncle, Miguel Santos, told Manhattan Supreme Justice Laura Ward. “No one has the right to . . . decide that somebody else’s life has no value. Nobody.”

A loudly blubbering Lithgow apologized to Pellerano’s family.

“I was wrong, I did the wrong thing,” he said, pausing as he sobbed.