Usher's ex-wife contends that she is taking a "defensive" approach in the pair's ongoing custody battle.

In Late November Tameka Foster filed court papers asking the Without You singer to lose joint physical custody of their children.

Usher and Tameka have two sons together, four-year-old Usher Raymond V and Naviyd Ely Raymond, two.

It was reported that Tameka claimed Usher ingested mind-altering pills in front of their children during a visit.

Tameka discounts these allegations.

"I never accused him of drugs," Tameka told Star magazine.

"My attorneys requested the test, not me. I'm merely in defence mode."

Tameka maintains that she is not to blame in this contentious situation.

"He started this, I didn't," Tameka continued. "My kids are my life. I'd never compromise."

A number of allegations are made against Usher in the legal documents.

Tameka claims the singer should seek her permission before taking their kids out of the state, but has consistently failed to do that.

She also alleges they are supposed to agree before hiring a nanny, but he has not approached her before doing so. Usher is apparently meant to ask her to care for the boys if he is away for more than eight hours, with Tameka claiming that hasn't always happened.

Tameka also wants to receive more child support from the star, as she feels his income has increased since their split.

The pair married in August 2007, but Usher filed for divorce in June 2009 saying they had been living separately for a year.