I did do a search and didn't find anything so I apologize if this has been answered before:
I've always wondered if we had any evidence to prove (or refute) Anne Boelyn's supposedly numerous affairs. I know that Henry was gearing up to marry Jane Seymour and therefore would be pretty motivated to get rid of her, but is there any evidence to support either side? Or is it all lost to history?
Historians wade in on both sides of the debate. If you're interested in the topic I would highly recommend Eric Ives' 'The Life and Death of Anne Boleyn' where he argues comprehensively that Anne's downfall was the result of a plot, likely devised by Cromwell, to remove Anne from power. She was, at the time, becoming a real threat to him and his interests. Starkey also partly endorses this theory, suggesting that Henry as a character tended to take direction from one chief minister. First Wolsey, then on Wolsey's downfall, Cromwell appears on the scene. Starkey suggests that the plot to have Anne removed from power was the last in a long series of escalating conflicts between Anne and Cromwell over the position of 'chief advisor.'
This theory is also supported by the fact that Anne was becoming something of a political embarrassment. Not only did she openly and loudly oppose Cromwell's reforms of the monasteries, which involved selling the land for huge profits, she advocated French interests, the Spanish ambassador refused to recognise her and she had just miscarried a second child. After the death of Catherine of Aragon, in the eyes of the Catholic church Henry VIII was a widower, and without Anne he would be free to remarry.
On the other side, G. W. Bernard would argue that while the charges brought against Anne in court have long since been proven to be false, there is 'no smoke without fire' and that not being guilty as charged is not the same as being entirely innocent. His book 'Fatal Attractions' outlines this very thoroughly and is based heavily on a poem written shortly after her execution, which alludes to several (more plausible) incidents.
TLDR: the charges against Anne in court have more-or-less been entirely refuted (she wasn't in most of the places on the dates written, neither were the men, on one she had literally given birth two days before) but the evidence on both sides is sketchy at best. Modern scholarship favours the 'innocent' theory, but devils advocate is still a defendable position. Likewise, in the event of a 'plot' being brought against her it's unclear as to which of the usual suspects (Henry himself, Cromwell, the 'Catholic faction') was responsible.