Nick Cannon is head over heels for his new bride, Mariah Carey, according to Jacob Arabo, who created the diamond sparkler that the actor gave the singer as an engagement ring.

"The way he came into the store, the mood he was in, I knew this was very serious," Arabo tells PEOPLE exclusively. "He said 'Jacob, I'm in love. This is what I want to do.' "

Though there's been no official confirmation of a wedding, the pair obtained a marriage license on the Caribbean island of Eleuthera, and Cannon's family confirmed the pair got hitched.

According to Arabo, Cannon, 27, came to Jacob & Co. two weeks ago and asked to have an engagement ring created for Carey, 39.

"He said he wanted something in pink, so he picked something in a light purple-ish pink. He was very involved and he trusted me to design the ring."

Despite the couple's whirlwind romance, Arabo said: "He loves her. That's all I know."

As for their compatibility, he added,

"[Nick] is an artist, she's an artist, so they have a lot in common. He was very, very happy. Happier than I have ever seen him. I've known him four or five years and this was a really happy moment for him, in his life."

I still can't believe he married her. She's old and she's so friggin big-headed. But I guess whatever makes him happy...