Still, a friend of Andy Mill calls the close relationship "the ultimate betrayal"

Since tennis star Chris Evert split from her husband of 18 years, Andy Mill, she’s been spotted with golfer Greg Norman, who had been one of Mill’s good friends.

And although Evert, 52, and Norman, 51, won’t say they’re a couple, Mill himself tells PEOPLE in its new issue: “These two people have really meant a lot to me for a long time. At this point I just wish them great happiness.”

But his ex-wife’s new relationship hasn’t been easy for the skiing champ, 53 – at least according to Paul Tejera, a Florida fishing guide and one of Mill’s best friends.

Tejara tells PEOPLE that Mill – a world-class fisherman who introduced Norman to Evert – never saw it coming.

“It was like the ultimate betrayal,” says Tejera. “To find out she was with Greg Norman was a shock.”

Evert, who declined to comment, separated from Mill in October 2006 and was granted custody of their three sons – Alex, 15; Nicky, 12; and Colton, 10 – when the divorce became final in December.

Norman split from his wife of 25 years, Laura, 57, last June (they have two grown children).

For their part, Evert and Norman became business partners recently when she signed on to create tennis academies in his resort developments, and were recently spotted strolling hand-in-hand in Sydney, Australia.

But they’re keeping mum on their status. “We’re very, very close friends,” is all Norman would tell reporters in November. “We’ll leave it at that.”