I wanted to romance him in both the first and second game even before my mind connected the "Wait! that's the same dude dot lol."
I remember in the second game you see him for the first time and it's like "wow that guys hot! Hope he's a romance!" And he wasn't
lol
So what I'm trying to say is I would ship Cullen with whatever character in whatever game I got to have him!
Also awesome story Hannah! Even though you were tricky and totally made us think it was the inquisitor who was getting some hot library action! 
I played the games out of order, so that definitely affected my view of Cullen.
My Hawke was relentlessly pursuing romancing Fenris so I didn't want to romance Cullen in the initial playthrough, but Cullen immediately caught my attention as this sincere, caring, worried guy who had a ton of crazy stuff on his plate. As the game progressed, I started to see his point of view more, and by the end of the game I was really impressed with his bravery and moral courage in finally trying to do what was right.
Then I played the first game and found out where he had originated, and... wow. That man has come a long way!
I think that's why I'm so optimistic about Cullen's future, actually. He's far from perfect and far from healed, but I still see a lot of progress and a lot of capacity for improvement with the right support. I don't think that in the past two games he was in an emotional place where he was ready for a romance, so I think it's cool that he finally is.
I'm glad you enjoyed the story, and that I fooled somebody about who he was in the library with! 