Pick a moment with Gen and Irene in The King of Attolia, any moment. Odds are it's heartwarming.
"You are treasure beyond any price.”
The king lifted a hand to her cheek and kissed her. It was not a kiss between strangers, not even a kiss between a bride and groom. It was a kiss between a man and his wife, and when it was over, the king closed his eyes and rested his forehead in the hollow of the queen's shoulder, like a man seeking respite, like a man reaching home at the end of the day.
Similarly, any interaction between Gen and Hiero in that same book.
This moment, from The King of Attolia:
"Am I no longer your Queen, then?"
Shocked, he whispered, "Always," breathing his soul into the word.
This troper melts a little at the moment in A Conspiracy of Kings when Sophos’ parents are reunited, and Sophos realizes how much his father actually deeply cares for his mother.