In the meantime you need to offer your husband any evidence you can that you are innocent, I bet they didn’t even say who you cheated with, right, because if so that person could have a real talk with your husband. Offer your theory, it sounds weak but I’ve heard it happen before and at least it might get him thinking about it. Ask him to give you the benefit of the doubt, tell him if that mail had any credibility to it, it would have solid dates, places, names, details. That it doesn’t is a very good reason to doubt it. The mere fact that it’s anonymous is a reason to doubt it. If you’re feeling lucky, ask your husband to ask for verifiable details to confirm (although they will make some up if pressed). Ask them how they "know". And don’t give any information, just get it. Perhaps you can poke a hole in it or use it to track down your anonymous detractor. Even better, have him ask for them to reveal themselves or "threaten" that he won’t believe them. He should use an account that it is plausible only he has access to, so he can tell them he won’t reveal their identity. That puts them in a hard spot.

You also need, to the best of your ability, to find out where this email came from… and if they admit it, you need to tear that person a new a$$hole. … and also try to secretly record any admission (maybe they feel like gloating?) so you can clear your good name. Who knows that you went abroad, and when? Who knows your husband’s email address? I will bet none of these people was actually in a position to observe you "cheating" (you were in another country after all) and you can point that out to your husband. Although he might accuse you of blabbing about it after the fact. Who has motive? Especially suspect people that use the same email service that this mail came from… you have decent but not great odds they were too lazy to use another service. You can point that out to your husband too.

Good luck. You can probably reset the passwords to the bank accounts at the bank, assuming your name is on it. I’m more worried about your husband going apesh*t on you. If he won’t listen to you and it doesn’t blow over, then I think he will probably make a move pretty soon. If you have no one to fall back on, and think he is going to take everything, then setup your own account if you have to, and move money (only enough to get by until you could theoretically get a job) into it, but understand this is not going to make you look better in the eyes of your husband. It makes you look a bit like a thief so you have to tell him if your motive was to steal, as opposed to not ending up on the streets because you’re so afraid of him, then you could have easily taken it all.

It really sucks to be you, I hope you’re vindicated before it’s too late.

If your husband is that enraged by what someone else said, without having any real proof or without discussing it with you, I would say you might be better off without him. He does not sound very level headed or real stable to me. But then again, neither does this family member of yours.

Any way you can find out for sure where this came from? Not that I think it matters. But surely, I can’t imagine he would have fallen into this type of rage with only an e-mail.

If the accounts are in both your names, he can not legally block you. You might want to give him a few days to cool down, then try talking to him again. If this does not work, I would contact an attorney. After only 9 months of marriage, if he acts like this, can you imagine what a lifetime with this guy would be like?