He said he had no choice. When Cole taps into his noggin and asks why he walked away from her, Solas's only said, "I had no choice."
It strikes me as very odd. Especially with the timing of his departure. Mid-kiss he stops and the fleeting expression on his face is something like a sad puppy being denied the only thing he wanted in the world. Most seem to believe this was a moment of epiphany and that makes a lot of sense, I am ok with that, even if I think whatever epiphany that could have been feels like typical fantasy soap.
Don't get me wrong. That stuff is like crack to me. His epiphany, if that is what it was, was likely related one of the following, no? "I am immortal, she is mortal. I can't deal with her dying on me. If only she were my people.. in another world I could love her without fear " or "She'll know who I am once I have that orb. She will hate me for it. I will be the legendary villain from her Dalish children stories. Better she hate me already and get it over with." I'll happily toy with the thought of endgame/DLC/DA4 Chesha chasing him down to prove how wrong he is. (O pretty please, give us this option, powers that be.)
But what if it wasn't an epiphany that twisted his face in sorrow? What if it was a sudden complusion. "I can't do this." Or more like something in his mind telling him with great conviction, "You can't do this."
He tells Cole, "I had no choice." Based on all we know, when has he ever failed to understand choice and consequence? That just seems like an uncharacteristic answer from someone so wise. My mind can't leave it alone. Am I crazy?
Don't answer that.
What if, like Mythal-bound Lavellan, he is also bound. The way he passionately argues at any inquisitor who drinks from the well speaks of possible experience to me. Fen'harel, but bound by the will of another. Likely also to Mythal. Just because he is peer to these powerful, ancient beings, doesn't make him immune to their handiwork. Could all of this be traced back to a loyal dog dancing on his master's leash? He thinks locking the ancients away was his own idea and it probably did resonate with his feelings of ancient elven society, but what if it was actually a compulsion from the murdered and vengeful spirit of Mythal. He tells Mythal-bound Lavellan that she will mistake Mythal's will for her own, and do things at her bidding without even knowing it. Is it because he's been dealing with the same thing for who knows how long, and has learned to recognize it?
Free to follow his own heart, until he isn't. If this is the case, he knows his predicament. "It would be kinder in the end."
It may also explain why Cole says Lavellan changes everything. But also can't. She changes Fen'harel's mind about modern elves. She changed his heart and the world outside the Fade is not lonely anymore. She changed even the Fade for him, when they met in a dream. But she can't break the geas. She can't change what he is compelled to do.
If that is the case, I sure hope our Lavellan get the chance to prove that wrong too, and break Mythal's hold over him (and herself should it exist). A hold that is likely infinitely stronger now that the spirit of Mythal possibly resides in his body.