The only question I have in regards to Solas/Lavellan in between the lies (and I honestly don't think he abused her in any question other than lying to her, the lying is a betrayal but betrayal by itself is not abuse) is the question of whether or not their relationship was actually "real" for Lavellan. Solas loves her and their relationship is real
to him. He had all the information and she never misrepresented herself. She, however, is in love with who she thinks he is and as he said "she saw more than most". She didn't see it all and has to work with what she has. For her, he's just an elven apostate who is a little stuck up and fade expert.
She knows he doesn't see modern elves as his people (just like Sera, ironically). She doesn't know she's falling in love with an ancient elf. She doesn't know she's falling in love with a man that her people remember as a god.
It's like falling in love with a vampire or a Highlander who never comes clean. You think it's real until the fog lifts, the truth is known, and then you realize you never knew them at all.
I think depending on the Lavellan in question, it's a betrayal she can get over. Not knowing he's the Dread Wolf allows her a chance to see him for who is as opposed to what legend presents him as. That said, I don't think they can ever truly be together until she has all the facts about him and is allowed to work through her feelings on the subject.