COLORADO SPRINGS, Colo. -- A former high school teacher in Colorado Springs faces sentencing next month after reaching a plea agreement on child sex charges.

Gwen Ann Cardozo, 33, pleaded guilty on Monday to sexual assault on a child by a person in a position of trust, admitting she had a sexual relationship with a male student who was 17 years old at the time.

Prosecutors dropped another charge in exchange for her plea.

The deal will require Cardozo -- a mother of four -- to undergo sex offender treatment and register as a sex offender. She may also have to remain under supervision for the rest of her life.

Cardozo agreed to deferred sentence of four years. That will allow her to avoid prison if she doesn't violate the terms of her probation. .

Cardozo taught English at Wasson High School for 10 years before resigning in March.

According to a police affidavit, a student teacher who was grading work for Cardozo last February found love letters written to Cardozo among a student’s homework assignments.

The letters referred to “doing it today” and ended in “I love you,” the affidavit stated. The school notified police the next day.

Cardozo originally denied having a relationship with the boy until threatened with a lie detector test. She then admitted having sex with the student three times a week for two months, according to police.

The relationship began when he was a senior, and lasted for at least two months, according to the boy.