My Lavellen hasn't really slept around since she turned twenty - she's mid thirties by tresspasser. She isn't all too interested in relationships - if they happen, they tend to be serious, and Solas is probably the most serious thing she's had in years. Still, she's practical. I think she immersed herself in work and duties and almost got over him by keeping herself so busy - when Cass mentioned getting married, she genuinely thought, hell yeah, maybe I could find someone. But as soon as she started discovering elfy ruiny stuff again, I think his absence was felt, and by the end he'd hurtled back into her life like a meteor, as quickly as he left, and it was like two years hadn't passed at all really.
I also have a headcanon where Surana is inquisitor, coming out of a difficult relationship w/ Leliana that finally broke up shortly after Kirkwall chantry blew up. She and Solas fight and argue because they'd very different - Surana's a bit wild, appears reckless at times, treasues her freedom more than anuthing - despite having too much in common - Surana LOVES magic, she's dead nerdy about it, despite her faith. She also believed in changing Thedas - she was a rebel mage who helped form an underground collective along the waking sea for refugees, mages, and elves, and she's always been one to fight the powers that be. It's... an interesting relationship which actually ends up being pretty beneficial and healthy in its short run. Surana challenges him to be better, she admires him deeply, and he wants to live up to that, to be the best he can be for her. And he helps her feel less alone on her journey, he helps her deal with doubts and despair that follow her, he takes the relationship very seriously and helps her be herself - not a role model, or a hero, or a display people want to see - for the first time in years, and helps her work out some of her trust issues that have arisen because of that. They're both lonely little wrecks who struggle with this world and I love them both.
I imagine Surana will sleep around a lot. I imagine until Solas, she often had open relationship like arrangements with a hardened Leliana, given their commitments and distances and trust in each other they once had. Sex is a refuge - likely, she takes all kinds of people to bed. I think by Trespasser she'll be..angry. So angry. Solas, she'd hoped, was the best of us - she was wrong on that count. The least he could have done is pretended not to love her, because by Trespasser, she was still hurting from his loss, more able to remember that hurt than the joy in her heart from being with him. I imagine she holds herself back from yelling. I also imagine that she's sick with concern for him - she knows he has struggled, just not what with - and probably will be an angry mess that throws herself into his arms before he can say a second word. I think she'd forgive him. Because he broke up with her, after all - she never got hung up on anyone else like this before.
I should mention, really, that I've spent the past two years in love with my best friend and it's taken me exactly that long to get over him. I think if he asked me out now, after all this time, I'd fall apart on the spot just because of how cruel it'd be. That's... coloured my thoughts on this. I believe that if a relationship is broken apart by external circumstance - say, distance - it's not impossible to rekindle at all. That said, heartbreak is fun to play but not so fun to live - I have, so far, spent more of my life trying to fall out of love and get over people than I have in relationships. Dragon age has been one of many methods by which I got over them. I am eternally glad I do not have Lavellen's luck.