The victim was hospitalised after she suffered 40 separate identifiable injuries during the attack in May last year.

But she initially lied to police about her wounds because she feared the 39-year-old would kill her.

The man pleaded guilty in the ACT Supreme Court on Wednesday to charges of sexual intercourse without consent, assault occasioning actual bodily harm, and property damage.

Court documents said the couple had lived together for only a few months at the time of the attack.

On the evening of May 12, the woman had gone to bed, while the man stayed up drinking and consumed three bottles of wine..

The victim was awoken by a loud smash and found he had smashed an empty bottle and sauce jar on the ground.

He said he was angry and the woman left to stay at her mother's.

But he grabbed her by the hair and threw her to the ground when she returned to take his keys.

He then stomped and punched the woman in the face and chest, yelling: "This is what you get for lying to me. No one f---- with me. All you are is a slut."

During the next 15 minutes, he choked her, told her he was going to kill her, and snapped her phone when she tried to call for help.

When the woman asked for a drink of water, the offender smashed two ceramic mugs over her head, causing a large cut on her head.

The victim showered before he sexually assaulted her in the bedroom and then went to sleep.

When he awoke hours later, he looked at the victim and asked what had happened.

He took her to hospital after he returned from work the following day and asked her not to report him to police, telling her he loved her.

The victim then told police and friends that she had been attacked by two men at a Belconnen club, before confessing it had been her partner and she feared he would kill her.

A medical examination identified 40 different injuries, including bruising and cuts to her head, neck, shoulder, arms, and legs.

He told police he bashed the woman because he thought she had an affair.

But he initially claimed the sex had been consensual.

Justice John Burns ordered a presentence report be prepared for a sentence hearing later this year.

He remains behind bars.