Bedtime help

cmanmom

I posted something similar on the preschool board but thought you ladies might help.

My DS is 4, and doesn't have overnights with his father so that doesn't weigh in.  Obvs. I am a single mom so I am putting him to bed 100% of the time.  He has before stayed overnight with my parents no problem.

So exH (DS father) was out of his life for 18 months and just recently came back in Aug. and has been using his parenting time = 6 hours e/o week (10am - 4pm) and I'm not sure if it's a coincidence or timing or DS age or whatever but there's that.

DS was to stay overnight with my parents (my mom watches him while I work so he is very familiar with her, and her house so that's not it either).  I went through his bedtime routine with him there and put him to bed and left.  My mom calls at 11 pm and DS had woken up and was super upset - she couldn't calm him down so she brought him home to me.  This was about 1 mo. ago.

Last night I had plans so my Dad watched him and was to put him to bed at our house (mine and DS) but DS put up a huge fight and was crying for me and carrying on etc.  When I got home at 10:30pm he was up, whining and watching a show.

What gives?  Is it his age?  That his Dad is back in his life?  Is he playing us? 

HELP!!  Thoughts on what it might be, and help on how to get him over it please!!!  TIA