I am 29M, my SO is 27F. We have been dating for about 1 year and two months. I have social anxiety, and this is the first girl I have even kissed. Things escalated quickly and we decided to start a live in relationship about 4 months ago. 
It was decided that we would split the household chores equally. I was completely fine with it, because we both worked an equal amount of hours. Even though I earned a fair bit more, I was home for roughly the same time as her and all was good. 
It was going great till 2 months ago, I got an opportunity to become a key member of an emerging company. I was a bit reluctant because of the work hours but my SO convinced me to go for it since there was a massive salary hike too. 

 It required a lot more extra effort from my part and I often work 12-16 hours a day now. I ended you liking what I did, and my salary almost doubled. The ratio was now about 5:1 in terms of how much we contributed. Not saying I don't let her treat herself with our money, I obviously did... but I expected to at least come home with less dishes in the sink and vacuuming done.

Apparently not, I often end up staying up till 12 am and wake up at 4am. I confronted her about this yesterday. She goes out to watch movies and binge watches Netflix, something we used to do together, everyday. I honestly couldn't handle it anymore.

Yesterday,I didn't shout or anything, I just told her that we should honestly consider changing the agreement and she should ideallydoing a little more work. When she said that I had promised on the 50/50. 
I told her straightaway that I couldn't handle it.
I told her that I would be fine with doing a good amount of things, just not an equal amount or the majority of the work load. 

She suddenly just broke down and slammed the door shut. Saying I was supposed to be a good guy but I had somehow made it all worst. 
Mostly because of the door muffing my voice, I shouted and told her I did my fucking best being a good guy for the people around me.( but I do confess that there was a trace of anger and aggression.) She told me to fuck off and I ended up sleeping in the other bedroom.


Today at work I was getting bombarded with messages from her friend's on how I am being a complete moron and should better bring a box of her favorite chocolates by the time I reach home.


I am at a local library now, honestly a bit stressed out....I genuinely need some help and even constructive criticism is welcome.

I honestly might be the asshole, this is probably more of a confirmation. I am ready to listen to criticism and improve myself in any way possible.
I am just stressed out.