Girls Aloud singer Cheryl also claimed she put the England star "through hell" by blocking his dream move to Real Madrid last year.
Asked if Cole, 26, misses the Gunners, she said: "Not any more, he loves it at Chelsea now. It got to the stage at Arsenal where he couldn't even have a conversation in the dressing room because nobody spoke English.
"He started getting paranoid because he had no idea if they were talking about him, or what was going on.
"Whereas at Chelsea he has John Terry and Frank Lampard, and he gets on brilliantly with them. I think things changed for Ashley when Patrick Vieira left. He was really upset and that hurt.
"The team spirit dwindled a bit after that, and he would come home unhappy. It's not easy mentally being unable to talk properly to your team-mates."
Cheryl reveals she met Cole when they were living in the same apartment block and the £100,000 compensation he received over a libel action paid for her wedding ring.
But she insisted Cole had made a mistake by detailing his contract talks with Arsenal when he famously wrote he nearly crashed his car over a revised offer of £55,000 instead of £60,000 a week.
"He shouldn't have written it, I told him that," she said. "It was a big mistake because it was written out of frustration and anger, and the way the media interpreted it made him sound awful.
"Ashley got caught up in all the hurt and frustration he was feeling and I agree that saying that stuff about the figures involved and so on was not a good idea.
"I read Ashley's book before it was published and I told him then that he should not put that stuff in about all the money. Because it is a ridiculous amount, whatever he ended up with."
Cheryl, 24, said she had opposed the Real move because it would have damaged her singing career. But she admitted she had not realised the strain of moving between two bitter London rivals would have on her husband.
"He went through hell, his eyes were dead until recently," she said.