My husband just learned today that his Citi credit card, which he has had for almost 10 years, was closed by Citi. When he called to ask about it, he was told it was because he missed a payment in January (so it's now over 60 days late). This is the only late payment my husband can ever recall having on this card, and he generally pays it off in full or close to full every month (he's done this since he got the card). My husband has never had any other credit cards, but he has had a car loan (paid off, good standing), a line of credit from a mattress store (paid off, good standing), and a mortgage (ongoing, no lates, and we've had it for 1 year now). His credit score has always been very good (typically over 750, or just slightly under, for many years), but the last time we checked our scores was a year ago, right before we bought our house, so we aren't sure what they are right now.
Citi has said they'll "send it up for review", but from what I've read, it doesn't often get the card re-opened. What other course of action should he take to either get the account re-opened, or deal with the situation (hit to his credit, getting a new card, etc.) if they don't re-open it? Will he have difficulty getting a new card from another company?
He needs to have a credit card asap (he has some travel for work coming up, and needs to be able to charge the expenses). Would it be a bad idea for me to add him as an authorized user on one of my credit cards? I'm not worried about him not paying for the charges -- we have a large amount of money in savings, and money is not an issue for us. And, with the exception of this incident, he has always been very responsible with money and finances (even though I'm the one who mostly manages them for our household). Besides... I know where he lives! 
I just want to be sure, before I do something like that, that I'm not shooting myself or him in the foot somehow.
TIA for any and all advice!
First, I'd call back CITI and speak to someone above a CS rep or Supervisor (i hate dealing with middle management. no offense to anyone). Explain the situation and find our what he needs to do to get the card back ASAP!
I'd also add him to your account. Having just one CC is a bad idea.
Starting Score: 600s
Okay, I am not trying to be mean here but this is not a guessing game. Lets take some responsibility and get your ducks in a row prior to trying to contact upper management at Citi.
#1: Pull his credit report. Find out if it is reporting as a 60day late or 2 30 day lates. Also look back to see if there are any other lates from Citi on his credit report. If I recall from other posts, Citi is the type of bank that will call and hound you when a payment is missed.
#2: Pull out the bill. The payment should be due about the same day each month and COUNT when the payment was sent by your husband and received by Citi so that you can validate whether it was truly late and if the lates are accurate.
#3: I recommend you both handle the bills from this day forward. 2 eyes and minds are always better than 1.
#4: After you have validated everything, then call Citi and talk to upper management. Explain the situation and the accidential oversight. Offer to establish an automatic payment plan for the monthly payments if that will help to get the card reopened.
IMO the reason the account was closed is that you mentioned that you made a large purchase while your account was in default status. To me that signifies a major red flag as the company was trying to mitigate an assumed loss that they might end up taking.
And I do agree with the others that adding him as an Authorized User (as long as you don't have any lates on that card) would be a good idea as well. In the short term, it can make sure that he has a card to use for his traveling expenses.