What shall I do?!:(

I have a 4 month old son, me and his father have been having a few arguments over access. I want him to step up and see his son more then once every week or two and stop giving excuses like 'I'm tired or I'm not in the mood' (he doesnt work, anxeity&Depression).. it all kicked off round his mums house and instead of an argument between me and him about his son it turnt into a massive argument between me and his mum. I'm disgusted with the way I was spoken to, shouted at and how she can even defend him when I'm looking after our son physically and financially 24/7. Me and his father have partially sorted things, became civil and came to an agreement on access but I'm still upset I haven't received an apology from his mum, it's like she feels no need to apologise because she's not exactly missing out on time with her grandson, she'll just see her when he's with her dad because they're living together.
Any advice?