After a few weeks in the Phils I can tell you that over her in the UK we have a very different perspective on time. Not that I think your partner is being very fair though, I agree with previous posts about trust being very important.
However, if you keep missing times when you have said you'll be in touch or be online, he maybe thinks he's not that important to you if other things always take priority over him. Its probably not the case from your point of view but that might be how he's taking it.
He might also worry that something has happened if you're not where you say you;ll be at a certain time, its difficult being on the other side of the world and relying on regular contact.
I remember before Bert got his cell phone (he's only in Phils for a few months as he works on ships so doesn't always have a cell when he first gets back) and I'd call him at his mums house, he's not there - most of the times I call - then arranging times with his mother to call back and he's not there then either, its very frustrating, then thigns start going through your head - is he avoiding me? doesn't he love me anymore? whats going on? why is he never there? - all crazy thoughts I admit but they do go through your head.
So really, spare a thought for him, have a little think about what you would think if he wasn't there when he said he would be, or doesn't turn up on line when he says he would be.
Sounds like you've both come along way together and he has committed a lot of time, effort and money to you and your relationship, it must be really getting him down to react the way he is.
Good luck and hipe it all works out for you
K xx