Sharing Household Expenses with a Boyfriend?

I have been dealing with the proper way of moving into an home which is already established. Meaning I met a guy almost 3 years ago and we finally decided for me to move into his home in September. I decided to give him 1,000 a month to contribute to the household that he already had since he was 23; he is now 43.

I did move in with my son who is 9. I asked after I moved in that maybe 1,000 is a bit too much knowing he was paying about $800 for the mortgage and I would just take over all bills even though I don't watch TV, I will still pay cable, all utilities, and groceries for the household.

Fast forward to a month later when I realize he no longer pays a mortgage and he makes a decent salary, as well as myself, but I don't want our relationship built off a business. I feel that is what it is in a sense even though we get along greatly. He states every month I am complaining about the funds given to him. I explained I don't have a problem contributing. I give my share on time. I just told him I feel you are happy about it and I'm not.

He compares me to his ex wife who never contributed to anything stating she wanted the man to take care of home like it was back in the day. I am very fair and understanding I just wanted him to know that 1,000 a month for something he had before I moved in is a sufficient amount and to let us re-visit the amount. I asked in January let me give him $800. I feel more comfortable with that amount, but he says no $900. I say okay let's see what happens in January hoping he would agree on the $800. We are now in January and I go to the bank give him his dough, but then feel like I am just being taken advantage of and he gets all upset and angry saying why did I move in then. "I said, wow I thought we moved in to build, to love one another, I didn't realized I moved in to be a business partner."

Mind you he has two children by two different mothers who he has to pay child support to. I am in no way trying to get out of contributing, but I am just saying let's be fair. He said this is fair and that all of the things he has to put up with, my son does have ADHD and can be an issue at times, is worth the money as well or he can just be alone since he wouldn't have to deal with arguing about money every month.

Please tell me am I being irrational and not fair or is he just not being understanding and not fair. I want us to come to a median, that is all. Please give me advice I really wouldn't want to break up for something so stupid.