Okay summing this up, just my opinion mind you. (and a lot has been said before, but hey it's late)
Let's see,
* Bioware creates a whole armada of LI's for ME2,
* They state they are curious to see who will cheat on their ME1 LI's because the new ones 'are so compelling',
* Then they design the generic Virmire Survivor scene on Horizon that applies to those romancing Kaidan, romancing Ashley and isn't too detailed to scare away new players,
* Shepard's Horizon dialogue has to be pretty generic too, so in one sweep it covers all 3 angles,
* To soften the blow to their fans, they add a simple mail to create somewhat of a romance presence,
* And those who didn't find the new LI's compelling get a picture scene right at the end of the game.
Now I read the forums quite a bit and a LOT of people are saying they found comfort in the arms of another. In my mind the whole Horizon scene was simply designed to even make it easy on players to find someone new.
Cerberus seems to have injected Shepard with an overdose of hormones because she's sniffing her crew for potential mates from the moment she sets foot on the Normandy, while the original LI seems to drift further away into the past because there's not much to go on really. Everything is designed to push you into the arms of another, even friendship dialogues are shortened with potential LI's because once you don't pick the obvious romance options, they stop talking all together and will have nothing more to say to you for the rest of the game...well goodie goodie.
Because I view things like I just described, ME2 made it very easy for me to stay loyal to Kaidan. And after seeing what the LI's in ME2 were about, I'm soooo glad I did. Truthfully, imo, both Shepard as the new characters deserved a lot more. I actually feel sorry for Shepard at times.
I hope her hormones settle down a little in ME3 so she can think clearly again and word her thoughts a little better. Because, I swear, if the reunion scene comes up with Kaidan and she leans back against a table to do that 'Hubbah, hubbah' thing of hers, I'll step into my tv screen to personally toss her into the aquarium to cool down.
Which could be fun actually