It was "Moonrise Kingdom", which is basically about a 12 year old boy and girl who've fallen in love and decide to run away together. They even get "married", lol. He recommended three movies total; the other two weren't romances, but he emphasized that he thought I'd like Moonrise Kingdom the most, even attaching the YouTube link to the trailer for it.
The guy is a former crush of mine from middle/high school. He didn't like me back, though. We met up a couple weeks ago for the first time in over 8 years, and he paid me a lot of sweet compliments, mentioned wanting to cook for me at some point, and even walked me home when it started to get late, and kept expressing that we needed to hang out again soon.