Ian Paton, 36, of Snowdrop Rise, St Leonards, was found guilty of strangling Kayleigh Hanks, 29, to death at her flat in London Road, Bexhill, on July 21, 2019.
On Friday (February 7), Paton was found guilty of murder following a two-week trial at Hove Crown Court.
Judge Jeremy Gold sentenced Paton to life in prison with a minimum term of 17 years.
He said Paton would serve 17 years - minus the 200 days he has spent in custody since his arrest - before being considered for release.
Paton killed his care assistant girlfriend after a row developed between the couple about Miss Hanks’ friendship with another man.
Paton had claimed he applied pressure to Miss Hanks’ neck in self-defence after she charged at him with a knife following an argument about a message she found on his phone.
During a two week trial, the court was told Paton had strangled Miss Hanks in front of their seven-month-old daughter.
Speaking on behalf of Kayleigh's family, her sister Emma said: "Kayleigh was a kind, thoughtful loving person that would do anything for anyone.
"She was an amazing mum, daughter, sister, auntie and friend. Living without her will be the hardest thing we will ever have to do; she will never be forgotten and will always be in our hearts.
"She wasn't just a sister to me; she was my soul mate and best friend.
"Myself, my mum and our family would like to thank everyone who has helped us through this difficult time, the support has been incredible. We would also like to thank all the police officers involved in this case because without them, we don't know where we would be, they have all been amazing. But most of all we would like to thank our family liaison officers from the bottom of our hearts; they have helped us through this traumatic, horrible time in our lives and no amount of words would ever be enough in our eyes to repay them. They are a credit to Sussex Police and wonderful individuals."
Sentencing Paton, Judge Gold said it was 'not surprising' the jury rejected his assertion of self-defence.
He said: "Kayleigh was 29 years of age when you killed her on 20th July 2019. She had borne you a daughter eight months before the tragic events with which this court is concerned and was obviously doing her best to make a family life for the three of you.
"Sadly, the evidence in this case clearly illustrates that your relationship with her was turbulent, to say the least. It has been described by more than one witness as “toxic”. In any event, it culminated in an explosion of violence on 20th July last year which culminated in you killing Kayleigh by strangling her.
"Putting your hand to someone else’s throat in an argument was something that you had done on previous occasions and you did it again on 20 th July, this time with fatal consequences.
"You attempted to persuade the jury that you were acting in lawful self defence in response to Kayleigh attacking you with a knife. Not surprisingly, the jury rejected that assertion. I have no doubt that you strangled Kayleigh in an explosion of anger and then went about deliberately cutting yourself with the intention of advancing a false defence. That was a cynical and reprehensible reaction to what you had just done – taken the life of your new born child’s mother."
After the sentencing, Detective Chief Inspector Andy Wolstenholme of the Surrey and Sussex Major Crime Team said: "Ian Paton claimed in court that he acted in self-defence during an argument with Kayleigh, who he said had come at him with a knife.
"But our investigation showed that his superficial injuries were self-inflicted.
"This was the tragic climax of a series of issues in their relationship in which each had accused the other of having affairs. But this was made worse by Paton's volatile personality and his tendency to react violently under pressure.
"For example, the court heard evidence of different incidents in which he grabbed two other women he knew but was not in a relationship with, and a man, by the throat for several seconds at a time, causing them great distress although no physical injury.
"This terrible crime has deprived a young woman of her life, has devastated her family, and has left a tiny child, aged just seven months and who was in the same room when her mother was killed by her father, without parents."