The girl's mother had a child to the man and was nine months pregnant with their second when she allegedly walked in on him assaulting her daughter, who was from a previous relationship.

The court heard the girl, then aged 11, was asked to leave the room and nothing more was said of the incident. The family had been living interstate at the time.

The 49-year-old man, who cannot be named to protect the identity of the alleged victim, faces nine charges including performing sexual acts with a child under 16 under his authority, aggravated sexual assault, indecent assault and inciting indecency.

Defence counsel Peter Pearsall told the jury none of the alleged incidents occurred.

Police claim the abuse took place between 1990 and 1998 when the girl was aged 10-17, at two locations in the Illawarra and at a NSW town.

Much of the alleged abuse occurred when the girl's mother was away for several days, the court was told.

When the girl had attempted to tell her mother in front of her stepfather he had pushed her into a table and then hit her mother.

The court heard the girl's mother and stepfather had broken up when she was about 13 years old.

Aged 16, she was kicked out of her mother's home and with no family or friends to turn to, lived with her ex-stepfather.

In the witness box, the alleged victim, now aged 29, said the man sexually assaulted her within a short time of moving in with him.

"I couldn't do anything. I was scared ... of getting hit," she told the court.

They had sex for the first time when she was aged 17 and the pair was living in a unit, she said.

From then on they had sex "all the time ... every day", she said.

The pair married in 2002 but separated a month later.

The alleged victim told the court the accused had asked for sex only once while they were married.

When asked by Crown Prosecutor Wayne Creasey why she ended the marriage, she replied: "I got strong enough to say ... 'I'm not doing this anymore'."

She reported the alleged abuse to police in July 2007.

The trial continues.