Henry VIII

 
On 7th June 1509, Henry married Catherine of Aragon who was the widow of his older brother, Arthur. The marriage was an alliance between England and Spain. However, the unification was illegal according to the Bible and had they had to gain special dispensation from the Pope for the mariage to proceed.
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Catherine of Aragon
The Dissolution of the Monateries
His Split From Rome
Catherine produced a daughter called Mary, but did not provide Henry with a male heir. Without a son to take over from him when he died Henry feared the Tudor family would lose control of England. By 1530, Catherine was too old to bear another child and Henry wanted a divorce. This was denied by the Pope. Eventually Henry decided to split from Rome and form the Protestant Church of England so he could divorce Catherine and marry Anne Boleyn.  
I believe the most significant reason behind Henry's split from Rome was his need for a male heir. Without a son Henry feared the Tudor family would lose its stability and control over England. Even once England was recognised as a Protestant country, Henry still continued to use Catholic practices and never made any major changes. However, during the Dissolution of the Monasteries his financial greed led him to destroy and ransack the Catholic monasteries. 
However Henry made no immediate changes to the Catholic services or policies. Apart from preventing all payments to the Pope from the English Church, everything remained the same. This proves that Henry's motives for splitting from Rome were entirely non-religious. Moreover he did nothing to outlaw Catholicism and so did not mind its following and influence. Immediately after the split, Henry did nothing to increase his annual income. It was only later that he gained anything significant financially.
In 1536 Henry dissolved the small monasteries and in 1539 he dissolved all the large monasteries. He took much of the land and the wealth. This period was called the Dissolution of the Monasteries. In fact between 1536 and 1547, he received an extra £140000 a year because of the monasteries. At this point, Henry's obvious intention was financial gain. He had fought in many wars in Europe and was extremely short on money.
Mary I
To conclude, I believe that Henry's prime motive for splitting from Rome was his need for a son. Both political and financial gain may have been responsible later on but they would not have been his primary reason at the time of the split.