Would you tell your parents the "big secret"

i2012do

So fiance and I have a secret, kind of. My fiance was married before. here is the brief background.
Fiance met a girl in high school, and they were together for about a year. He joined the military nad was set to deploy to Japan, before he deployed her parents suggested tehy get married "for the extra money and security". They were 18. Her parents kept pressuring him. The night before he left for Japan- his gifrlfriend came over with wedding rings and said she wanted to get married. The morning before her left they went to the court house and got married. On the way to the airport- they stopped at Subway to celebrate. (real lame I know).

Fiance goes to Japan for 6 months. Comes back to their "apartment" (he had never seen it or lived in it, seh got it while he was gone)...starts to move in his stuff. He spends 2 nights there and realizes he doesnt want to be with this girl. He moves back to his parents. They try to work it out, it doesn't work out. She starts dating someone else. They get a divorce

I met him while he was in teh processing of moving out of the apartment and getting a divorce.

We never told my parents.

Originally mymom asked if he had been married before (I told my friend who told her mom who told my mom she thought it was him, but it coulda been another firends bf)...and I said NO. I don't know why I said no, I had only been dating FI for 2 months and my mom is very very judgemental. I felt like she was going to judge him based on that and not on who he was.

TO be honest, it's been 4 years since his divorce. No one even talks about it, I totally actually sometimes forget. His grandparents never knew he was married. Only his parents and some aunt and uncles.

I told Fiance he should tell my mom. I feel bad holding this in and its causing me anxiety thinking that someone is going to mention his Ex at our wedding!! Like "this is so much better than his first wedding etc". His aunt mentions her ALL the time to me, and she always liek "we love you so much, she was so awful to him!" etc so i don't want her to say anything to my mom.

I also, don't think its MY place to tell my parents his secret. He's a big boy and has to tell her, it's not up to me. I am almost positive my mom has an idea (i mean that lie i told 3 yrs ago that like "NO my friends mom must be talking about someone else " she probably knows when her kid is lying)...but she never mentioned it.

It also caused issues because we can't get maried in a catholic church (my parents are so upset about this) bceause hes been married before, and I keep lying and telling them its for religious reasons. (FI isnt catholic)

If you were us, what would you do...and how would you tell?! Its been so long- I don't want my parents to get upset that I was keeping a secret for 3 years but honestly it never came up and i kind of forgot he was- until we had to get the divorce decree to get our marriage license next year!