To cut a very long story short:
Fell pregant with DS a month into the relationship. It was a shitstorm so we ended it. He asked me to have an abortion frequently after that until I reached 24 weeks. Barely saw him as a baby and started building up contact through the second year and now DS is three. (a lot of work on my part but they started bonding gradually. However I've always made it clear that he could walk away and shut the door if he'd rather, as a dad who doesn't care is no good for DS anyway but it seems to have all gotten much better and he's been havign him overnight once a fortnight for 2 weeks).
His dad died when DS was a year, so I always try to factor in the fact that grief is a horrific thing and it was very unexpected. He feels like he has to live with his mum now his dad is gone which is fine if that works for them.
But his mum recently decided to move 250 miles away for cheaper housing and to leave the town (memories etc). He went with her and now contact has all gone crap.
He's called to say he's very stressed with driving so far for visits/returns (I don't drive but the family knew this upon moving) and can't see/have DS for the forseeable future but will try and continue payments.
I never know what to think because the whole 4 years (pregnancy included) it's been saying one thing (I love him, I want contact) and doing another (missing visits, dropping him off early because DS has been stressing him out and just saying how stressfull DS is etc well yes he's a toddler, no shit, plus I have him 90% of the time so I bloody know).
I'm being a bitch, aren't I?
I'm just so fed up of always being the understanding one who leaves the door open no matter what. I feel bad because I do empathise with him. I can't imagine that sort of grief but why did they move so far away (his mum seems to love seeing DS) and why have a half in half our approach? If you don't want to move nearer and can't handle visits but don't want to cut contact then what are you actually doing? Is it a breakdown? 
(Also dealing with a whole heap of shit at our end atm which might be making me a grumpy bitch, though I'm trying my hardest to compartmentalize it)!
Scuse the essay 