Spoilers
In the TV series, it was episode 26. When he wanted to run on the ice and Shen Jia Ping wanted to stop him as the ice was thin and it was dangerous. I can't fully remember if that's the only time he did it.
Well, I finished reading the novel in Chinese. I'm not entirely sure which version of the character I like more, perhaps it is because I watched the TV version first. The novel version is more realistic though in terms of PeiLin giving up his love for Jin Wan and the ending makes it such a tragedy.
Speaking of endings, I was told there were 4 versions. I've only read 2 versions; the first was where he ordered to have Xin Zhi murdered, but JingWan took Xin Zhi's car and therefore died (under the orders of MuRong Feng. The second was where apparently a car accident was staged. Xin Zhi and their daughter both died and she ended up killing herself with the gun PeiLin had given to her. I found the latter both tragic and ironic, although the more preferred ending in comparison to the first, as the gun was originally given to her to "protect herself". I'm still searching for the other 2 endings. If anyone has access to the Chinese versions of the other 2 endings, please direct me
Also, out of curiosity, do you guys actually like the fact that she married Xin Zhi in the novel?