As the couple prepared for the birth of their first child, a boy due in July, "Stephanie felt they weren't connecting and decided they should go to counseling," a source close to the situation tells PEOPLE. "It was getting dire."
Finally the truth came out, and it stunned Anderson.
"In one of the counseling sessions, Sam thought he would make it better by confessing," continues the source. "He [admitted] that he had cheated on her with multiple women throughout the course of their courtship and marriage. He told her everything."
Shocked by the news, "Stephanie decided to split" from Poueu just two months before their son is due, says the source.
When approached about the infidelity allegations, Poueu, 28, didn't deny the claims. He tells PEOPLE in a statement, "The circumstances and specifics of our marriage and our separation are extremely difficult and private."
Now Anderson, 33, and Poueu are left trying to pick up the pieces of their broken marriage amid preparing for the arrival of their baby boy this summer.
"Our focus is on Stephanie's continued health through her pregnancy and the delivery of our son," Poueu tells PEOPLE. "We are excited to be blessed as his parents and are focusing all of our energy and attention on doing what is best for his future. He is the most important person right now to both of us."