Hi...welcome to the forum
I'm not an expert but it sounds to me like he's holding a grudge because you left him.
Try and pinpoint what is going on right before he goes -- you said he's doing it in front of you. Maybe there will be a hint of the reason.

I'm not an expert but it sounds to me like he's holding a grudge because you left him.
Try and pinpoint what is going on right before he goes -- you said he's doing it in front of you. Maybe there will be a hint of the reason.