[Boppidy]

I've been with my boyfriend for 6 months. He asked me to move in and when I accepted I offered to help with bills and he said "don't worry about it." This conversation happened THE DAY I agreed to move in..
His divorce is almost final and he'll take away about 20k in debt. I have no debt, but I make 35k and he makes 150k. (he doesn't have to pay alimony and there are no kids involved) He probably doesn't know exactly how much I make and I'm an artist, so it's very up and down anyway. I have some family money in stocks and some other money saved. We talk about marriage and I've explained that once married his debt is mine and what I've saved will help pay the debt off. We also agreed that I will continue to save for a down payment on a house for us, which I believe might be one reason why he said not to worry about the bills when I asked to help.
So, here's what happened! I've been living there for exactly 1 month and everything was wonderful... Until a few nights ago he casually says to me "we need to sit down and divide up the bills." I felt so small, foolish and angry. We had a long talk about it and he said that nothing has changed and that it has nothing to do with his divorce or his feelings for me. He claims he only suggested it because I offered to pay for the phone and storage (I was trying to contribute and as these bills came in I asked if he'd like me to pay them)... he said he thought me offering meant I wanted to "divide things up." It seems like this is the excuse he came up with because I questioned why he changed his mind.
I had to go out of town the next day, so over the phone I asked him what he had in mind for me to pay so I can begin to budget. Then he said to keep it easy I could just take a few utilities. I asked him to send me an email of his thoughts because this is my first time living with someone and he's done it before. When I received his email he had the bills and rent broken down 50/50 at 1150 a person. A big jump from a few utilities.
To help you further understand, let me explain that he's told me before that he paid every bill while with his ex.. every single bill while they dated, when she moved in with him and after they were married and even though she made 75k... at a job that he got her (I don't know why he disclosed all of this information about his ex, but he did.. It'd probably be better if I didn't know!) They had separate accounts, he paid everything, spent his entire savings on a house down payment and she paid nothing while saving for her retirement. It seems as though he gladly paid their living expenses, which is why I didn't think anything when I offered and he said "don't worry about it".
After reviewing his breakdown of the bills, we had a talk and I explained how it really bothered me that he said not to worry about it and then wanted to divide things up. He explained why he did this (as I explained above) and then said it was a misunderstanding and that we can keep things the way they've been... so I said OK... Even though now it feels REALLY awkward!
I'm out of town, but when I get back I was thinking I might by choice, happily and casually take over some utilities.. Maybe all of them and let him just pay the rent.. maybe just a few of them since he first said "don't worry about it".
What do you guys think? I don't want to burden him or for him to resent me.. I don't want things to be weird about money with us. Should I pay more than some utilities? Less? The $1150 he suggested?. Suggested AFTER I moved my stuff in.. AFTER he said not to worry about paying the bills.. let me just say that one last time! ;)
I've always WANTED to contribute and help out. I've paid for things here and there, was saving to take him on a surprise birthday cruise in March, have offered to help pay things along the way and have focused a lot on saving for our future. I don't feel like I WANT to as much since he basically changed his mind, sent me a bill and tried to reduce our relationship to me being his roommate. Why did he do this? Everything was great before this happened. What should my next move be? Am I overreacting?
Ok, thank you so much for your help and responses.

[ChihuahuaMomma]

Your relationship is 50/50 should the bills be. No matter who makes how much. That's my opinion and experience.

[liz28]

When I lived with my ex he made more, double to be extact, he paid the rent. I paid the cable, light, and phone. We split the food. Paying the electric should not be a burden. Also, I think you both should save for a down payment not only you.

[Romefalls19]

Yep 50/50 is the way it should be, although I don't agree he told you don't worry about the bills then changes his mind. Lesson learned - Make the person sign an agreement stating that fact

[Tuscany]

Before my husband and I got married we lived together. To pay the bills fairly we opened a joint account where we each put in a certain amount of money each week. Out of that account the rent, ultilities, and home repair was paid. We still had our own money for spending as we saw fit.