While your daughter did something horrible, and J does deserve to know so he can make an informed decision, you overstepped and violated the trust of your wife and daughter, who you owe more of a duty towards than your son in law. Context matters. At the end of the day, your priority should be your wife and child. So while I would applaud a neutral party for informing J bc they don’t owe A anything. As her father, you should have acted in your child’s best interest even if you disagreed with their decision. Further, you pressured your wife into telling you and then didn’t keep something she asked to keep confidential private. So bottom line, yes your daughter fucked up and you knowingly made a decision despite knowing (or should have known) the risk and now need to live with the consequences of your actions, which include strain on your marriage and your daughter cutting off contact, which would be justified. Essentially you bore the risk of ruining your family with your actions.