A source told the Sunday Mirror newspaper: "Johnny told the restaurant owner he's always had a weakness for being too trusting, and said that was what had caused his problems.
"Obviously Amber is making some shocking claims about him, but he gave the impression of someone who wasn't worried. He doesn't accept the things that have been said.
"He also said their relationship was great until they got married."
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Despite the controversy surrounding him, Johnny was reported to have looked relaxed and happy at the after-party.
The source added: "Johnny was in a great mood. He was chatting to the girls at the party, and certainly didn't seem to have the weight of the world on his shoulders."
This comes shortly after it was confirmed that Amber's restraining order against her husband had been extended.
The Magic Mike XXL star filed for the court order against Johnny at the end of May after filing for divorce from him a few days earlier.
The restraining order - which was originally granted when Amber claimed Johnny hurled an iPhone at the actress' face - will now stay in place until August 15.
Johnny has denied the accusations made against him.
- Bang! Showbiz