Although John Proctor plays a part in the conflicts of the Crucible, it's Abigail Williams who is more responsible for the conflicts in the plan.
John Proctor is a good man. He hates hypocrisy and has a strong moral compass. That doesn't mean he is perfect. He did commit adultery against his wife with Abigail Williams. John's wife knows about it, and Elizabeth and John both suspect that Abigail is using her newfound witch accusing power to eliminate her "enemies." In act two, Elizabeth is mentioned as a possible witch and Elizabeth suspects the reason is to get rid of her so that Abigail can pursue John. Elizabeth even tells John to have a word with Abigail and dispel her notion that John's adultery is equal to a marriage promise. In a roundabout way, if John had not committed adultery with Abigail, she might not have accused as many people, but I think that is a stretch.
A reader could make the case that John is also to blame for the events in Salem because he possibly could have put a stop to them sooner. Salem looks at Abigail as a saintly young girl who has the power to help root out the evil of witchcraft that seems to be gripping Salem. All John would need to do is admit to the town that he committed adultery with Abigail and that would immediately remove Abigail's "halo of goodness." John doesn't do this though because he fears for his good name.
Despite all of that, I still think Abigail is more to blame than John, because it is Abigail who STARTS the accusation process. Sure, John MIGHT have been able to stop it, but if Abigail never accused anybody in the first place, then the ensuing hysteria never gets started. She may be young, but Abigail is old enough to know what she is doing and understand the consequences being brought on the accused. Without Abigail, nothing happens. With John's confession, the events MIGHT have stopped, but even John doubts his word is enough to overcome the grip that Abigail has over the town.