Despite challenges from a health scare to a lying ex, Teen Mom 2's Leah and Corey Simms say their relationship is stronger than ever.
On Tuesday's all-new episode of the MTV reality hit, Leah, 18 -- whose October nuptials to Corey will be shown later this season -- gushes about how she knows her beau is The One.
"At first there were ups and downs, but I think we're doing really good now," the mom of twins tells a pal. "The thing is with me and Corey, we do things very fast. From the very beginning, we got pregnant. But with [him], I feel like I'm happier than I've ever been in my entire life." (Watch an exclusive clip above)
Unaware at the time of filming that Corey was about to propose, Leah knew just what she'd say if he asked for her hand in marriage.
"Corey was joking around, saying stuff about getting married and having another kid -- I think he was just being funny -- and I don't know if he would ask me to marry him, but I'd be like 'Yes -- hell yeah!'"
For Leah -- who split from Corey for six months after cheating on him with an ex-boyfriend -- her feelings are a refreshing change from their early days as a couple.
"I knew that if I wanted us to be a family, I had to trust him," Leah tells UsMagazine.com of Corey.
Corey is planning a Valentine's Day for all three of his girls, which will include "a candlelit dinner" for his wife, he reveals.
And the 20-year-old dad to 13-month-old twins Aliannah and Aleeah, seconds his wife's notion that their bond is unbreakable.
"We both grew up in split-up families, and we don't want that for our girls," he tells Us. "We've already been through so much, there's nothing that can tear us apart."
Teen Mom airs Tuesday at 10 p.m. (EST) on MTV.