I need a rant (it's a long one)

Before I fell pregnant with my little boy me and his dad had talked at length about having a baby. Within 3 months of trying, I conceived. He has a daughter from a previous relationship and he told me that he did absolutely everything for her. So there was me thinking we'd be equal in what we do for out little one. I'm starting to think he's told me what he wants me to hear. One morning last week I was washing up breakfast pots and bottles ready to get them sterilised when I heard my other half comment about our son doing a poo. I was busy so told him to change it. Less than a minute later he comes in and says he going work, I asked if he'd changed the nappy and he ignored the question. Off he went, I lay our son down on his mat and he'd done a poo. His dad left him in a dirty nappy all because he couldn't be bothered to change it. He had a day off last week as I'd bought him a Driver Experience for father's day. He came home and our son was still napping so he said he was going on his game - which was fair enough. Half hour later our son wakes up so I said to my partner I'm taking him to soft play, are you coming? His reply was 'no, I'm going to finish building this base and then go out on my bike for half an hour'. So he refuses to spend a bit of quality time with his son. He comes home from work has a 5min cuddle with our son then sits on his phone and completely ignores his son even when he's trying to climb up onto his dad's knee. I understand that he works full time but I work part time and don't get the luxury of picking and choosing as and when I can be bothered with my son. The days I don't work he expects to have a tidy house and all the washing done but he doesn't think to help me out. I haven't been well the last few days so would really have appreciated him taking our son off my hands just whilst I had a lie down to recharge my batteries. During the first 5 weeks of our sons life, the other half would actually take him off my hands when he came home from work to let me get some sleep. About a week or so later it stopped. It was me doing every night feed and by our son being 5 weeks old I was diagnosed with post natal depression. At this diagnosis he helped doing every other night feed. Again that didn't last long. I'm absolutely exhausted and feel like I'm running on fumes. I don't feel like I can bring this conversation up with him as he's the sort that'll just get in his car and dissappear for a few hours rather than talk it out. We moved into our own place in September and I already feel like packing mine and our sons belongings and going back home to my parents because at least I had the support if I did need a bit of a break.