In his most extensive comments to date on the failed deal, Fernandes said in interviews published Friday that massive Malaysia Airlines union resistance was to blame and implied that the carrier had deep problems to resolve.
"I was off blood pressure pills as soon as the swap was off. I'm serious," he told The Edge business paper.
"Sometimes you need a bit of a kick up your backside. When we have built fantastic operations at AirAsia, we didn't appreciate it until we (saw) something else," he said.
His comments appear two days after AirAsia announced it is setting up a strategic planning centre in Indonesia, away from its Malaysian headquarters, with Fernandes expected to lead the expansion of regional operations from there.
AirAsia had agreed in August last year to buy 20.5 per cent of Malaysia Airlines under a strategic tie-up aimed at turning around the national carrier.
But the share swap deal was pulled early last month after pressure from Malaysia Airlines' powerful employees union, who feared job cuts and other cost-reducing moves.
Fernandes said Malaysia Airlines' problems could have been fixed under the tie-up.
"Yes, there will be short-term pain but you have to make the business successful as you cannot be on life-support," he told The Star newspaper..
"(But) you reach a point of why waste time talking... I'm glad it's over," he added.
With Fernandes moving to Indonesia the airline will announce on Monday a replacement to head its Malaysia operations.
Fernandes said he would still be heavily involved in the day-to-day running of the airline and not leaving anytime soon but was keen on a succession plan.
The former music executive took over the airline a decade ago and turned it from an ailing outfit with two planes into one of the region's biggest success stories.
Last month, AirAsia posted a 4.0 per cent increase in first-quarter net profit with the company citing a solid business model as the reason. It also posted a record quarter revenue of 1.17 billion ringgit ($367 million).
Malaysia Airlines, on the other hand, reported its fifth consecutive loss, amounting to 171.8 million ringgit for the quarter ended March 31.