I don't see that you did anything wrong or that you should feel badly about and it sounds like you still have a couple relatives (your husband and uncle, for example) who know the difference between right and wrong.

I would not necessarily fault the children, they cannot know the whole story or be expected to know what is at stake, not having had loans or been lied and cheated on in such a manner as your sister-in-law used her brother, your husband. It is unfortunate it is their mother who did wrong as they are not learning well from her, as you can see.

I would hold your head up (your sister-in-law should be the one ashamed to) and go to the wedding, enjoy those people who enjoy you and greet but don't hang out with those who do not. You had a right to cancel the loan, after all, it was in you all's name, not hers!

As a matter of fact, I would call the better business bureau or whoever and complain about the lender that made the loan without any proof; most legitimate places require driver's licenses, etc., picture, proofs of signature, etc. That was identity theft and if they did it to you/your husband they do it to others and your sister-in-law isn't the only guilty party but an accomplice helping them know they can get away with it; they would have made money on the deal so they didn't care who paid it!

In the future; experts say to never cosign for anyone, just give them the money or object (car). What you are actually doing is giving someone else your credit rating! Don't give others power over you like that. You get a loan and make the payments for it so you keep control and they pay you back (or not).