Shocked? So were we, but the giddily engaged couple, both 26, who have known each other for a little over three months now, tell PEOPLE exclusively they are "redefining the term 'YOPO' " from 'You Only Paradise Once' to 'You Only Propose Once.' "
Congratulations! How does it feel to finally be out as an engaged couple?
Lacy: It definitely still feels surreal.
Marcus: Hiding it and having [to spend time in] safe houses and covering our trails was definitely hard. It's still a whirlwind for us!
What do you say to the naysayers who doubt your relationship?
Lacy: We actually calculated how many hours we spent together and how long it would've taken us in real life to date and get that far. It was approximately six months!
Marcus: The main difference between Bachelor in Paradise or The Bachelor and The Bachelorette is if we don't get a date card, we still get to spend time together. So yeah, it's within a month's span, but within that month, you get a lot more time.
Lacy: Timing is everything. It happened naturally for Marcus and I in Paradise. We treated it as if it were our everyday life. We both have a lot of responsibilities in our careers [Grodd is a sports medicine manager and Faddoul owns an elderly care facility], and Paradise allowed us to let our youth come out.
Lacy, you were stuck between Robert Graham and Marcus in the first episode. Why did you choose Marcus?
Lacy: The first time I met Marcus, he was really timid and quiet, but he was so stunning. I was really intrigued. I think if that event with Robert didn't happen, Marcus and I wouldn't be where we're at. Marcus really stepped up after that and made it known he wanted to get to know me, so that's when I decided, "Okay, this is it!"
Marcus: I was pretty determined. She's physically beautiful, but just spending time with her and talking to her about our lives and our experiences, this girl surprised me with her mind and her questions and her ideas and her future. I definitely fell in love with who she was as a person.
When did you each know you were in love?
Lacy: The moment that I went to the hospital. Marcus wanted to be by my side the entire time. I didn't even know him that long. I was like, "Wow, I can only imagine how much he'll be there for me for the rest of my life."
Marcus: After that hospital time, we would lay by the beach together, just being so comfortable. Falling asleep next to her, I think I knew then I was falling in love with her.
Marcus, you entered Paradise just shortly after breaking up with Andi Dorfman on The Bachelorette. Did meeting Lacy put your feelings for Andi into perspective?
Marcus: I think you meet certain people in your life to make you a better person and to make you realize what you have before you. I came to an understanding why all these relationships in the past and the show with Andi didn't work out. It all makes sense after meeting Lacy.
When are we going to hear wedding bells?
Marcus: We definitely want to wait a year to get married at least. We want to do it right. We get one shot at this!
Lacy: We are actually going to enjoy our engagement. We've talked about it and I've been on Pinterest a lot [laughs]. He sends me bridal magazines, so he wants it to be on my mind. He's coming to see my home and I'm going to see his home, so we're going to decide after that where we're going to live together.