In the past couple of weeks, Stan has totally fallen in love with his dad. He is cuddling and wanting to play with him all the time in a way that he never really has before. I remember reading that in little boys there is a testosterone surge about 4 years old which leads them to create a stronger allegiance to their dads, so I don't know if this is the start of that, or if (or as well) he is thinking on some conscious or unconscious level that since I am going to be tied up with the baby he had better get dad 'on side'.
It's coinciding with some real separation anxiety about me - he has NEVER been upset to be dropped at his granny's before, but the crying and begging the last couple of weeks have been really distressing.