@Dire I think Taegun does like him, but he thinks Jaeha doesn't like him and views their relationship as a 'business deal' so Taegun was upset and gave Jaeha 'some space' or whatever or thinking time will fix things, that Mc would go back to him eventually, though he did keep watch over him all the time. Based on what you said, after the divorce I think Taegun realises he might actually loose Jaeha forever, so he takes the initiative to communicate and get back together.
I think why Jaeha wants to run away. he has lingering issues and unhealed traumas from childhood, he view himself as a burden to the world. Both of them has issues and communications is not going to be easy, but they like each other and don't treat each other harshly. I like both of them and rooting for them 
Holy ramble