I don't know that it would lower sexual abuse to allow priests to marry, but it might help. I don't think they molest simply because they can't have sex with women. It could very well be that these men are just predators who are attracted to a place where they have to swear celibacy because they think it will stop them from acting on their desires.
In history priests were once allowed to have marriages and sometimes even just had what were referred to as "mistresses" although the practice was later outlawed to provide a social appearance of "purity" and "chastity." For the sake of appearances this policy may be fine but for a group of men that will have healthy and regular urges the policy is inhumane. In order to find release and passion they now turn to children and unwilling individuals in order to "save face."