My DS is 4 and spends roughly 50% of his time with his dad (flexible throughout the week as we work shifts). When he comes home from being with his dad, even if he's only been there for a few hours, he refuses to go and see DP or even go in the same room, saying that he is scary. Once he has been home a little while, he is absolutely fine with him again. We have no idea what is causing this, and DP is understandably quite upset by it. Ex-H has been told before about bad-mouthing DP in front of son. Please help!
(background - ex-H and i separated 18 months ago, DP and i now have a 4 month old daughter, and up until very recently DS has been absolutely fine with everything)