That's it really. His contact and interest in our son has dropped significantly since he got a new girlfriend and it is so frustrating.
Before he got a new girlfriend although he wasn't a wonderful dad at least he saw DS often and made an effort. He would have DS while I was working which was sometimes 10+ hours and it was fine and I trusted him but since he got a new girlfriend he doesn't seem to play with DS and its like he wants to be elsewhere.
His attitude has got so bad it's at the point where I don't trust him to have DS alone anymore.
He does no parenting what so ever, just turns up half heartedly plays and leaves.
We both are happy with him coming to my house to see DS I should also add, he lives far away and couldn't be arsed to learn to drive while I was pregnant despite me offering to pay so therefore he has to get the bus here and back which is too long of a journey for DS. And tbh he probably wouldn't be bothered to anyway!
Does anyone have any advice about him always arriving late and leaving early? He's currently an hour late and I am sick of it. He doesn't even bother to let me know he's going to be late and acts like I'm the one being unreasonable. He knows he's welcome to stay as long as he wants, I am more than fair to him.
I raise our child alone 24-7 and he can't even manage to get here for the time he said. It's ridiculous! I am doing a university course and every free hour I can get is important so while DS sees his dad I do my work and neither seem to be happening.
It's not the end of the world at the moment because DS is too young to understand but I want to nip this in the bud before DS gets older and is sat waiting for his dad to show up 
Should I tell his dad if he's late he can't see him? It feels harsh but I'm not sure what other way to try kick his arse into shape and realise I wont let him carry on and potentially hurt our son like this.
No flaming please if I've said anything that could have been taken the wrong way. Constructive comments only please, I DO NOT want to stop contact before someone accuses me of that I just want him to realise he can't do what he wants and he has a responsibility to his child.
Thank you for any advice!