Lady Mac:
As he was watching the baby, I think he was searching for some kind of resemblance to him. I think Jing knows nothing happen with YY. His depression is due to the fact that he broke his promise to XY and believes he's not worthy of her.
He got it at the end by reflecting to comment his sister-in-law remark(Huo's wife) when the baby's born. The boy would not recognized Huo as his birth father, he would only call Jing 'Dad.' I think Jing's character is a kind of boring, he would say 'yes and okay' to whatever Xiao Yao say, he's a reserved and submissive man. But behind the kindness and smiles, he has screw mind of business and political strategist. At the end Cang Xuan realized that the brilliant Feng Long's plans was originally Jing's strategies. I think Jing is pretty firm to what he believed in, he fully supported Cang Xuan when no else else has confidence in him, he did all the havoc to ruin XY's wedding to FL. Jing has no ambition for imperial court, Tong Hua created Jing amongst ambitious men and strong women around XY. As XY said 'because his kindness that she's fallen in love with.'
I think I love their love story. It's sweet, relevance, enduring, strong, and they both grew from their struggles.