Chrysta says shortly after she met Bobby, he and his son moved in with her and her children and then they became engaged.

“We were an instant family; it was perfect,” Chrysta says.

TELL DR. PHIL YOUR STORY: Have a Volatile Teen, Parent or Sibling?

However, Chrysta says that mood soon changed when she saw a different side of Bobby’s then 4-year-old son.

“Bobby’s son appears to be an adorable, charming, sweet little boy, but he's not,” she claims. “Bobby’s son is dangerous … He's actually planning on how he can hurt me or even kill me.”

Chrysta claims things have gotten so scary that one night she woke up to find the now 8-year-old standing over her with a screwdriver. Then, recently, she claims she found a knife hidden inside the boy's mattress.

“I live in constant fear,” she says.

WATCH: Why Women Say They Are Begging Their Loved One To Leave Her Fiancé

Chrysta and Bobby agree that his son’s behavior is causing a strain on their relationship.

“I felt for the longest time Chrysta was just trying to make something wrong with my son,” Bobby admits. “Every time I didn't take one of my son's behaviors as serious as I should, it would start a huge argument between Chrysta and I.”

Chrysta says she asked Bobby to move out of her house and now wonders if they should even get married. “I love Bobby, and he is the man that I want for my children. But, everyone in my life is telling me to run as fast as I can,” she says.

In the video above, hear more about the 8-year-old boy’s alleged behavior. Does Dr. Phil think the couple should walk down the aisle? See what happens on Thursday’s episode. Check here to see where you can watch.

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Ways Woman Claims Fiance’s 8-Year-Old Son Has Terrorized Her