"When I first found out the charges were going to be withdrawn, my initial thoughts were with my son. He should never have been put through what he's been through."
Muliaina said he was looking forward to going back to New Zealand and moving on.
"I don't know the girl or know what happened. All I know is I'm not the person that had done what she said."
Muliaina, 35, was accused of touching a 19-year-old woman "on the bottom over her trousers" on a busy nightclub dance floor in the Welsh capital, Cardiff, on March 7, hours after he played for Irish side Connacht against the Cardiff Blues.
The fullback was arrested after the final whistle of his team's European Challenge Cup quarter-final defeat at Gloucester in April.
Still in his team tracksuit, he was captured by cameras as he was led to a police van.
"The way I was treated, I suppose I was a bit aggrieved by it," Muliaina said.
"Not being able to comment publicly has been very frustrating. While I understand the police have a job to do, the manner in which I was arrested I find difficult to understand. I can still hold my head up high and ... this is no stain on my character."
Muliaina thanked friends, family, his new club, Zebre in Italy, and even strangers for supporting him.
Wales News reported Muliaina's defence lawyer John Charles Rees, QC, saying the decision to prosecute was outrageous.
Muliaina wanted the trial to go ahead so he could clear his name, Mr Rees said.
"It's just wrong that they've now offered no evidence at this late stage. My client has had this matter hanging over his head for some time."
