Ben Blakeley, 22, killed Jayden Parkinson, in the countryside on December 3 last year - 24 hours after she told him she was expecting his child.
After strangling the teenager, Blakeley buried her body in his uncle's grave at a cemetery in Didcot, Oxfordshire.
The former binman was obsessive and controlling and threatened to post intimate videos and photographs of Jayden on Facebook after their break-up, hoping she would kill herself as a result.
A jury at Oxford Crown Court yesterday found Blakeley guilty of Jayden's murder.
Blakeley, of Reading, Berkshire, had denied murdering Jayden but admitted her manslaughter.
Judge Patrick Eccles QC said Blakeley had spun a "web of lies" to cover up what he had done.
His brother, Jake Blakeley, 17, admitted a charge of attempting to pervert the course of justice by helping to dig the grave in which Jayden was later buried.
The jury of six men and six women was dismissed having failed to reach a verdict on whether Jake Blakeley, of Didcot, prevented a lawful burial for Jayden.
The Crown Prosecution Service has been granted seven days to consider whether they will seek a retrial for Jake Blakeley.