I was always a bit puzzled by the exchange with Solas in the Fade where he said "everything changed" and I am meant to assume has some sort of romantic connotation, which I didn't at all but found I had to take the heart icon at this point or not proceed the romance. It is the one place where I still have sympathy for Solas because she is really pushy at this point and he is clearly uncomfortable. Of course subsequent events explain why he is feeling so awkward.
There is an ambiguous line in Trespasser if you take the dialogue option that has her saying "The Dread Wolf did take me". He responds that he would never have slept with her under false pretences (or something like that). So am I simply to assume this is him saying that his love was genuine (like he does at the end of the main game - "what we had was real"), or is he saying that the reason he didn't sleep with her was because he hadn't told her who he really was?
See, I wouldn't really characterise her as aggressive there, and Solas isn't uncomfortable so much as hesitant. At several points throughout the romance, they do this little dance: Solas puts something ambiguous out there which makes you go "Did he just..?". Lavellan then generally asks for clarification. And then he makes it much clearer that yes, he did mean that. Even with the first kiss - her kiss is a simple kiss, and he's like, 'Wait, you didn't do that right, let me show you' 
Several more examples I remember:
S: (mentions her grace)
L: So you're suggesting I'm graceful.
S: I am declaring it. It was not a subject for debate.
S: ... I felt the whole world change.
L: Felt the whole world change?
S: Figure of speech.
L: I know what it means. I'm more interested in 'felt'.
S: You change everything.
(Balcony)
S: (talks about morals and spirit)
L: What does this mean, Solas?
S: It means I have not forgotten the kiss.
Solas is not the shy rabbit running from Big Bad Lavellan. Dude puts feelers out there, but yes, he does generally wait for her to confirm her own interest before he'll do the same.
As for that line from Trespasser, my understanding is that you're meant to interpret it in either of those ways. They left it up to you.