NWR: Co-parenting, step-parents, step children...I need to vent

Ok so my son has been living with his dad for the summer & he comes home most weekends. My son will be 8 next month & this is the first time we've tried this. I must be honest, I'm not liking it. My son is not used to being away from me this much & he's constantly asking me to stop pass & give him a kiss or come get him during the week for a few hours. His dad lives 20 mins from me so it's not a small commute. I've been trying to be super mom & run to his every call but I've decided I'm not going to do that anymore. I keep asking him does he just want to come home & he says yes but then he doesn't want to go to my aunt's daycare during the day while I work...well sorry kid, mommy has to work to take care of you! He's currently with my mom, he stayed with her overnight & instead of going back to his dad's house he wants me to come get him after work then take him back to his dad's house tonight. I told him no. I explained to him that if it was that bad at his dad's house he...