Annie and David’s marriage has been thriving unlike those of other "90 Day Fiancé" stars. Despite their 21-year age difference, the couple has managed to stay in love for a substantial amount of time. Fans are now very interested in knowing the secret to their happy marriage. Recently, the couple made an appearance at The Highlight Room in Hollywood California, reports Yahoo. ET’s Lauren Zima caught up with the two lovebirds and asked them the secret to their thriving marriage.

It should be remembered that Annie and David faced some serious challenges, early on, which almost jeopardized their marriage.

Surprisingly, they managed to get past all those relationship issues and keep their marriage intact.

David and Annie's secret

The two stars first met in Thailand through a mutual friend. They went on to appear in "90 Day Fiancé" Season 5, and again on "Happily Ever After’s" Season 3, where they have become household names. Most importantly, they have managed to enjoy and preserve their marriage, unlike fellow cast members. David and Annie revealed that the greatest secret of making any marriage work is for couples to always stick together regardless of anything. Furthermore, the two advised couples against letting any third party ruin their marriages.

The secret has worked perfectly for David and Annie and, on November 1, they will be celebrating their 2 years of marriage.

At the moment, the couple appears to be in a better place and have overcome various challenges that threatened their relationship in the beginning.

Advice for other '90 Day Fiancé' couples

David and Annie have some pieces of advice to give to other stars who want to preserve their marriages. The two stars believe sticking together, loving each other, and working on their relationship are essential to a happy marriage.

Truth be told, the "90 Day Fiancé" couple has faced a lot of marriage issues that they did manage to overcome together. There was a time Annie and David got themselves in serious financial trouble. But by staying together and helping each other out, they got past the challenge.

In the meantime, David and Annie are living happily together in Scottsdale, Arizona.

However, they are not planning on having any kids together soon. They also don't seem to be bothered by haters and critics.

There is more drama lined up for "90 Day Fiancé" fans. The much anticipated new season will air on November 3. The season returns when "Before the 90 Days" finale airs on October 27. Fans are set to watch David and Annie who will feature in "90 Day Fiancé: Pillow Talk."

Viewers of this show will get to know whether Tim Malcolm is transgender or not. Previously, his girlfriend Jennifer Tarazona claimed he was gay never wanting to have sex with her. Her sentiments have raised a lot of questions, among fans, regarding Tim’s gender.