erica ginnetti , 35 , was sentenced to 30 days in jail , 60 more under house arrest , 100 hours of community service and three years ' probation .
she pleaded guilty in a pennsylvania court in december to having sex with a 17-year-old student .
she tearfully read an apology letter in court friday to provide closure for the teen .
married mother of three said she has mended fences with her family and became a fitness instructor .
a judge told ginneti her ` sexual hunger ' had devastating consequences for two families .
she first approached her victim in may 2013 when she chaperoned the senior prom and invited him to come work out at her gym .
two months later they met at starbucks and drove to an industrial park to have sex in her car .