I go for the hay roll and proud of it 
Hey, am I the only one who romanced Kaidan only in ME1 and only because he was the only option available and then ... Garrus?
No offense but Kaidan was too well-groomed and in ME3 his continuous 'I don't trust you Shepard what are you doing with Cerberus gnagnagna' makes me want to smash my shotgun on his teeth every time. I'm always happy to cause him a headache 
Garrus has always been by my side also when Cerberus. Good bye Alenko, enjoy your headaches 
I played a renegade and started to find Alenko a little on the too-nice-guy side. The ME1 romance was fine. Didn't rock my socks, but it was fine. And then ME2 came out and I read that the Virmire survivor was going to be limited to cameo-only. I thought what the heck, I didn't want to play a game without romance and then wait another two years just to watch that romance pick back up. Forget it. Garrus was right on top of my list. I dug him. He was awesome. And then Horizon happened. That really knocked my socks off. He not only stood up to her, he was mad. He yelled because he cared. His heart was on his sleeve. And he wouldn't be a yes-man and follow her down that rabbit hole. He stuck with his principles. I respected that. I admired that. I know that whole thing was one plot hammer, but I loved it. That follow-up letter sealed the deal. I was perfectly happy to wait. No complaints whatsoever. And the way they reconciled in ME3 was beautifully executed. The tense moment with guns drawn on each other, the waiting by the elevator, the will-they-or-won't-they build up. I continued to be a renegade and found Kaidan to be a fantastic paragon balance, the yin to her yang. The renegade lines worked well in the romance. It felt like he just smirked at the hard-ass attitude like that wasn't going to faze him at all. It was great.
I consider Garrus to be the iconic boyfriend of the series. He's great. I'm envious of the dance scene in the end. I do have a Shepard that romanced him, but Garrus was the best thing about that playthrough as I found that particular Shepard to be boring (played as 100% paragon to get different lines, even got laughed at by Jack for it =p). I liked that Kaidan and Shepard went through fire and came out stronger for it. Blackwall and the Inquisitor have a similar path where their relationship got tested and hopefully got stronger for it (we don't really see much after Revelations so this mainly relies on head canon territory).
I'd say Garrus is the guy I'd have a beer with after work, but Kaidan is the man I go home to. But yeah, it was this close before Horizon happened.
(And I really, really liked the Jacob romance. I was really looking forward to their reunion in ME3, probably more than Kaidan and Garrus. Different writer though. ME3 Jacob is from an alternate universe. I can't even be mad at him because that isn't him. It just isn't.)