My Life At This Point

I really need advice from someone. I don't know if what I think is right or not, but here goes. I've been married to my husband for almost 6 years now and I've always known since day 1 that he had 2 kids from a previous marriage living in his native country. We lived in the states and everything was going ok, we had our son and then bad luck hit us and he was deported back to his native country and I decided to move back with him and our son of course and that's when everything started coming down, we didn't have enough money anymore and because he has the 2 other kids he had to give child support obviously. I saw all these things as normal but then when his daughters came to visit him it was always distinctly clear that he paid more atention to them than our son, like for example he'd always carry them and play with them and give them affection but always yelled at our son for doing something. I told him what was going on and even mentioned that my aunt had noticed the same thing but the only thing he said was "That's how I am". That still continues to this day but less. The worst part comes economically. We don't earn much in the business we own so he works as a part time taxi driver to help pay the bills and his daughter's child support. But most of the time I have to deprive myself of something I want to buy just so that he can take that money to his ex, which by the way I forgot to mention that he goes to see every week to give her money, but i have suspicions that they are still together, plus he's said in more than one ocassion that he still loves her "but not like that, cause she is the mother of his kids" If I want to buy a pair of earrings or something really simple I get criticized over spending on something that isn't a necessity and that i shouldn't buy it, if i end up buying it then the next week he's complaining about it when he has to bring money to his ex. He never wants to go out anywhere with me, like last week he was complaining and had a fight with me when I asked him to go to a concert with me (which my mother paid for the 2 tickets), He said "I don't go to that bullshit" but when his daughters ask him to go anywhere he immediately says yes. He hardly ever takes our son out to play, only when his sisters are here and we only celebrated his birthday once where with his daughters it's celebrated every year and he has to buy them brand new clothes and shoes and he's only bought our son clothes once (the rest has been bought by my parents or given as a gift) and shoes never. He also never wanted to change his diaper when he was a baby but I guess that's something men hardly ever want to do. But I'm pretty sure he has changed his daughter's diapers! One time we went out all of us (including his ex) and the two of them were walking together and I felt totally abandoned and if I had left at that point with my son (too bad I didn't know how to get around at that time) he wouldn't have even noticed I had left until maybe an hour later. We are waiting to go back to the states maybe another 5 years unless something happens sooner but I don't think he really wants to go back, maybe it's cause he's with his ex and he doesn't want to leave her or his kids. I totally understand that he has them and he has the right to buy them things and be with them and give them all the affection but he should be fair with all of his children including our son and me, after all I am his wife and he was never married to his ex, and treat us equally.