"Luann is over the moon in love with Thomas," a source tells PEOPLE

LuAnn de Lesseps and Tom D'Agostino Jr. Are Engaged! See Her 8 Carat Diamond Ring

She said yes!

LuAnn de Lesseps is engaged to Tom D’Agostino Jr., PEOPLE has confirmed exclusively.

Get push notifications with news, features and more.

“Thomas was planning on a Valentine’s Day proposal during their upcoming vacation in Vail, but couldn’t wait and presented an eight-carat canary yellow diamond ring before they got there,” a source close to Lesseps tells PEOPLE. “LuAnn is over the moon in love with Thomas and considers him her soulmate and is so happy and grateful to have found love a second time.”

“The happy couple are celebrating this week with their ski vacation in Colorado,” the source continues.

Lesseps, 50, was married to Count Alexandre De Lesseps, 66, from 1993 to 2009. The pair share two children, son Noel and daughter Victoria.

With the upcoming marriage, the Real Housewives of New York star will lose her courtesy title of Countess, but her businesses, The Countess Collection: Styled for Living – which includes her apparel and jewelry collections on Evine.com – will continue.

D’Agostino, 49, previously told PEOPLE that the couple was introduced by a mutual friend about nine months ago, and more recently reconnected while each was dining separately at The Mark Restaurant by Jean-Georges in Manhattan. Sparks flew between them.