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The wife failed to anticipate it. According to sources with knowledge of the relationship, Lilly Jay, the wife of married "Wicked" co-star Ethan Slater, was "completely blindsided" by the relationship allegedly between Ariana Grande and Slater.

Rumors have been rife that Ariana Grande is dating Slater.

An insider said that the impact of these rumors on Jay is tremendously negative. The insider said it is awful, especially since they were best friends in high school and they share a child.

"She's a mess," a source reportedly told Page Six.

As a couple, Slater and Jay celebrated their 10-year wedding anniversary in November of last year. They've been filming "Wicked" together in London for the past year, and sources say that she's the reason they "suddenly break up now, when nothing appeared wrong between them," the source added.

Even in an Instagram post for Mother's Day two months earlier, Slater, 31, gushed about his "wonderful" wife. "Happy first Mother's Day to the most loving, caring, and wonderful mom/person in the world," he wrote.

There was a picture of their son's hands in the post. Since then, he changed his social networking app privacy settings. The "Wicked" set was visited by Jay, 32, and his infant, according to production insiders. Grande, 30, is also said to have spent time with the couple.

Earlier this week,it was reported that despite their separation in January, Grande and her real estate agent spouse Dalton Gomez were still "incredibly amicable." Together, they reached this shocking decision.

Before January, they were having issues, but an insider informed us that they still wanted to be best friends. Slater and Grande haven't officially acknowledged their new relationship, and their reps haven't answered any of the press' qestions.

What went wrong between Ariana Grande and her husband Dalton Gomez is the subject of a source's explanation. According to a source who spoke with PEOPLE after the couple's breakup became public earlier this week, "Dalton is very religious and was committed to making it work, but Ariana had moved on." The luxury real estate agent, 27, and the Positions actor, 30, "have been quietly and lovingly working on their friendship" after their separation earlier this year, an insider told PEOPLE on Monday.