Hi there,
If you don't mind me saying, then coming from an unbiased side you are being a little harsh on him. I can understand your shock that he has kids and has been married before, but there a couple of key things to consider.
Firstly, arranged marriages are customary to tradition within certain families, but this does not guarantee happiness and it certainly doesn't mean he wanted to do it. If he split from his previous wife then he did so because he wasn't happy with that relationship.
If he has found a relationship with you to be close enough that he would both marry to you and confess this part of his life, then I would expect he was seeking some sort of understanding or comfort back.
Secondly, this likely is a touchy issue for him and he probably knew it would cause a bit of an uproar if he told anyone, which is why he said that you should feel lucky, in that he would hardly tell anyone else that side of his past unless he trusted them. That's why the "should" part of him telling you is the thing that would prevent him from telling you any further, he doesn't have an obligation to anyone reveal past marriages (arranged or otherwise), the only thing that decides it is whether he "wants" to tell you, and pushing the argument that he is obligated to tell you may push him away from revealing anything further.
Thirdly, if you don't mind me asking how does this change things for you? Sure he has had kids and a wife before, but if he is not in contact with them then how will it affect your everyday life? I would imagine that at the time of posting this you may have still been hurt and feeling betrayed by the lack of telling you beforehand, but there are many good reasons why it would be best not to say, especially if he himself is trying to move on.
In parting I would like you to think about the above points and consider that there is pain in both sides of this tale, I hope for both of you that you can come to an understanding of each other's pain and move on. Listen without judgement.
Hope this helps.
The past is the past...and it doesnt affect you,i agree he should have told you before marrying you...and let the chips fall where they may it sounds like he has a trust issue....he couldnt trust the person he is planning to spend the rest of his life with...with this info...why....and now youre probably not going to be able to trust him...i disagree with giving him a pass on it because its a touchy issue....what if other touchy issues come up while married...its okay to keep secrets? I do feel he is obligated to disclose EVERYTHING if you all are going to be partners in life there shouldnt be surprises like this popping up and you both need to talk about it i believe in order to move past it...and once you move past it....you shouldnt throw it in his face when an unrelated arguement occurs