Marcin Kasprzak, 25, was today found guilty of attempted murder at Leeds Crown Court after he Tasered his partner Michelina Lewandowska and buried her alive in a cardboard box.
Co-defendant Patryk Borys, 18, was cleared.
Marcin Kasprzak attacked Michelina Lewandowska, 27, the mother of his child, at their home and then bound and gagged her with tape.
She was placed in a box and buried in the ground in a wood near Huddersfield, West Yorkshire.
Kasprzak, 25, denied attempted murder but was found guilty by a jury at Leeds Crown Court. Co-defendant Patryk Borys, 18, was cleared of the same charge.
Miss Lewandowska escaped from the box despite it being covered in earth and a tree branch. She used her engagement ring to cut herself free and pull the box apart then flagged down a passing motorist.
The jury, which retired to consider its verdicts on Thursday last week, heard that Miss Lewandowska, who is Polish, was attacked by fellow Pole Kasprzak because their relationship had come to an end and he wanted their three-year-old son, Jakub.
Kasprzak, of Penistone Road, Huddersfield, told the court he only meant to scare Miss Lewandowska and did not intend to kill her.
Borys, of Rashcliffe Hill Road, Huddersfield, did not give evidence.
Both men admitted kidnap at a previous hearing. Kasprzak also admitted possessing a prohibited weapon.
Judge Peter Collier told them they will be sentenced on January 13 next year and ordered a report to be prepared on Borys.