When you start to feel like your heading towards out of control , leave the situation , take a walk , or a jog anything that allows you step back and regroup. Grounding skills are great for this.

Also tell your partner before/if you decide to try this ... That way they aren't left in the dark as to why you just left the situation.

It's good you handed over the financial stuff to your girlfriend, Since she is doing all the meals and shopping .. maybe you could pitch in .. help making meals, or clean up around your home.
I only say this because sometimes people pass off chores that upset them to significant others and then find out down the road that significant other doesn't want to just take care of it ALL and they become resentful ..