By the 1530s the crown was quite poor because Henry had spent a lot of his father's money on attacking France.
The Valor Ecclesiasticus, suggested by Cromwell, listed all the properties owned by the Church and it showed a large annual income. This obviously would have been tempting to Henry.
The monasteries were highly corrupt. There were issues with celibacy, living life in poverty, lack of education and an overall lack of monastic vows. By the 16th century, people had no respect for monks. Getting rid of the monasteries got rid of this issue.
Luther published De Votis Monasticis which said that monastic life had no spiritual basis which had an immediate effect on religious ideas.
To fully break with Rome, Henry needed to get rid of the monasteries and Henry wanted to become fully Protestant.
The main opposition to the break with Rome came from the monks. Although the monasteries signed an oath that denied the pope, it was uncertain how far they meant it.
Henry wanted more attacks on France and so the money gained from the dissolution would come in handy.
The break with Rome gained support from members of the mobility and the dissolution looked good to them.