Adams told Retail Week that last week's reports saying that he had signed a contract to join the fashion retailer were premature.
'I never really started at Monsoon', he said. 'It was my intention and Monsoon's to work together, but it wasn't right for me.'
Adams declined to detail the reasons for his departure, but said the decision had been made amicably.
Adams was poised to replace outgoing Monsoon chief executive Rose Foster, who leaves in May to take the helm at La Senza. He was to have stood in for Monsoon group finance director Mark McMenemy for the first two months until his departure in March before eventually being promoted to chief executive.
Trading at Monsoon has weakened since its signature style fell out of fashion with shoppers.
For the six months to November, like-for-like sales were down 6 per cent, with pre-tax profits slumping 5 per cent to£24.2 million. There is persistent speculation that Monsoon chairman Peter Simon wants to take the fashion retailer private or that he may try to buy the company's international arm.
Adams said he will remain in retail and continue to look at options in the UK and abroad.
Monsoon was unavailable for comment.