This is how I see the afterwards of their last scene in ep 9x04. I was listening to Arrival of the Birds when I was writing this so if you want to hear it while you read it, it's a beautiful feeling. Trust me. Thank you! :)

"Listen to what your son just tried to pull off." Donna mocked in front of him.

In that precise second, his mind fell into a whirlwind of feelings; a mix of admiration, pure bliss and absolute certainty. He observed her red locks loose over her shoulders, her smile while she told Lily about their recent exchange of words about marriage and engagement. That woman right there, was his woman. Not in a sense of possession; that would be the last thing he would want, to possess her. But his woman as his favorite woman in the world, in life, in existence. He would always exist with, for and because of her. Her eyes shut in the middle of a big burst of laughter. He was half listening, because the other half of his attention was too hit by the beauty of the instant. They just told each other they would always be together no matter what, and they even talked about marrying. Not that the papers mattered… but the union, the strongest desire of remaining united for as long as their lives last. Every single step.

"Okay, it was really nice talking to you, Lily, and we'll sure be there soon." he could hear Donna saying.

"Oh, I hope so, dear. It was my pleasure. I'll expect you two soon! Love you"

Harvey said some last final words for his mother. "Love you too, mom."

And then, Donna hang up. "She's so nice."

"Yeah. She's dying to meet you."

"Do you think she will like me?"

"She likes you already, I'm sure." he leaned closer, and took his hand to her cheek. Her eyelids flutter softly, the touch of his hand easing her mind from the rest of world. Then she turns her head to the side, and kisses his palm very softly… before looking at him. Her eyes, those powerful pieces of biology. "Ah, you're gorgeous." he whispered. Too caught up in the perfection of the moment, none of them cared or analyzed what they did or say now. That was something they would have to get used to; being calm with each other. There is no more danger now, and after so many years of running, hiding, deceiving themselves and blocking feelings, they were slowly tearing the walls down. It would take time, but they were making a really good progress, Donna thought.

"You too." replied Donna, getting closer and taking his lips in hers. It was slow, tender, sweet… them and nothing else. No rush. His hand never left her cheek, and he caressed it while observing every inch of her face. "I love you." he whispered.

"And I love you." she replied.

Then came another kiss, which progressively became a little rougher. Her arms wrapped around his neck, his body hovered over hers, her pants ended up on the floor, and just like that, in the simpleness of her couch, with their clothes still on, they were them. Truly and genuinely. No need to run. Slowly and gently, one day at a time.