It'd been an eventful day so Mara retired to her room. Neverthlessm she felt more restless than restive and found herself pacing a bit. suddenly, she sensed another person in the room.

She was glad to see him, but this was the second time someone was hiding on her balcony! Seriously, she needed to tell Leliana to get her some sort of lock. Heck, even Dagna could...well...maybe not, that might involve minor explosions...
"I thought you'd be dropping by." Mara said, smiling. Although she had thought there would be a knock first...
"I just wanted to thank you for accompanying me to that ruin. I just wanted to--" He came closer, seemingly drawn to her against his better judgement. "I just had to see you." He said softly, right before kissing her. He pulled away.
"We shouldn't be doing this, Milady."
Mara wanted to frown but instead chose to tease. "Why? A vow of celibacy? A dead wife?"
"No."
Finally, Mara did frown. "Is it because you're a Warden? you've got this obligation to fulfill?"
"It's not that." He disentangled himself entirely from her arms and put his shoulders back. "You've got to end this, now. I don't have the strength to." His body was held back by his own will, but his words were beseeching her nonetheless.
She took some moments to consider, as much as it probably pained him to wait.
"What can one Grey Warden do?"
"Save the ****** world, if pressed."
That passionate response had won her respect immediately, when she'd met him. The admiration came later, as she asked him about the Wardens and traded clever innuendos. Well, she had given the innuendos, to his mild embarrassment, and that had won him some points on her end as well. So much had happened. She'd struggled with accepting her role within the Inquistion. He'd given her a wake up call with his harsh words on the ramparts. He was part of the woman she was becoming. She wanted to be strong, like Cassandra. She wanted to stand for something, like Blackwall did with the Grey Wardens.
He'd been trying to warn her away, saying his life was full of darkness, ruins, and death.
Now here he was, in her room, heart on his sleeve, and was asking her to end things. almost speaking, she paused again.... but, no, this was nothing like the romp she'd had with Iron Bull. Blackwall was an admirable man. He shouldn't keep himself from seeking happiness because he had responsibilities. And neither would she.
She had her answer. "No. I'm not letting you go." and she closed the distance he'd created between them.
From within his arms, she kissed him gently, then slowly pulled back.
Blackwall relaxed his hold on himself and passionately kissed her back, so passionate she backed up until her bottom bumped the balcony railing.
Let's say Mara didn't have a problem with being restless later that night.