So, after honest opinions please.
EX P is the type of man who wants what he cannot have. I feared he would get bored with our DS and was initially reluctant for him to have contact due to his inconsistancies in the past but have doen my utmost to put my own personal feelings of hurt aside and encourage, support and frankly push a relationship between him and our baby who is 8 months.
At the beginning when he was only seeing him for a short time (once a fortnight, an hours contact, supervised) he was desperate to be in touch and kept on about how much he loved and adored ds, how much he missed him and was very gushy over him etc.
He has recently, the last 2-3 weeks been tailing off gradually, little by little....
The reason for this in his explanation is that he is working really hard, in order to set up a business to provide for his kids financially and set them up for life. Admirable yes, but does that make his tailing off contact ok? 
I email him every night when ds is in bed, telling him what he has done, eaten, any new developements, provide short video clips and/or photos as he said he missed him SO very much and these were his life line.
But over the last month he has gone from thanking me profusely on return of each email, to emailing occasionally or the next day, to now rarely responding at all. He used to txt me every morning to ask how baby slept, these have stopped completely. He was until last week phoning daily to ask after him, 4 days without contact at all last week and yesterday, I emailed him to ask when he was in the area in order o see ds as he had only managed 1 short hour last week and at this age I feel little and often is best for him to build a relationship. He did email me back for once, and I was encouraged by his promise to call me today and arrange a day/time to have contact with ds this week. Surprise surprise no call
Now its obvious he is not making DS his prority at the moment, and I DO know he is setting up a buisiness that is going well and that he working all hours. So is this acceptable? I feel worried/sad/pissed off that he is losing interest in DS and has trailed off in his want/need for contact and it feels like he wanted him at first but as is typical with him, he got bored and moved on to the next rush which is his work. Am I being unreasonable and should I cut him some slack as it is just work?
If so, how long do I back off for and when do I have the right to be miffed that he is too preoccupied with work to fit in DS?
I do appreciate his ethic that hes doing it all for his kids (he has 2 others who he is not with either) but in my opinion, kids dont care about money or Dad having a great job or business to leave them, all they care about it having a parent who wants to spend time with them and loves them enough to make them a priority when it counts 
Am I wrong, and does it wound like hes losing interest or is this a legit excuse? x