Minesh Parbat was driving at 60mph when he crashed in West Sussex in March last year.
His girlfriend and mother-of-two, Lisa Watling, was thrown from the car and the 28-year-old died later in hospital from her injuries.
In the aftermath of the collision, Parbat was discovered by members of the public with his trousers and underwear around his ankles.
Watling was found seriously injured in just a T-shirt and bra.
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"I make it clear that the blame for this tragic accident is entirely yours."
During the trial, Parbat denied anything sexual had taken place as he drove, adding that he had instead struggled to get Watling off him before crashing.
Parbat later added: "It's got sexual tones, but it wasn't sexual because nothing happened."
In a statement, Watling's family said: "Our lives have been ripped apart, leaving a wound that will never fully heal. However, the two real victims are Lisa's children.
"They will never have that soft comforting voice they know and love whisper goodnight, safe in the knowledge that when they wake up in the morning she'll be there to greet them.
"As a family we feel relief that some kind of justice has been seen. It feels like a very small step towards gaining a degree of closure.