Lyle Menendez and his wife, Rebecca Sneed, quietly ended their marriage after more than 21 years together, but she remains a key figure in his life despite rumors of a cheating scandal Sneed says are baseless, PEOPLE has learned.

The couple tied the knot in 2003 while Menendez was serving time for the 1989 murders of his and his brother Erik's parents.

Lyle Menendez is reportedly now dating a 21-year-old British college student after ending his more than two-decade-long marriage to Rebecca Sneed.