How to talk to SO about his son? Nothing I say is ever good enough
Me (27F), my SO (38M) and his son (14M) have been living together for a year. I won't sugarcoat it, it's difficult. But before we moved in together, my SO and I agreed upon a set of house rules (that were never enforced while my SO and his son were living together). These are some basic things: saying "Please" and "Thank you", washing your own dishes after a meal, helping to keep the home clean, etc.
And then there are a set of rules especially for the SS. He's obese, so with the help of a dietitian my SO is trying to help him to lose some weight (I tired to help too, but have been practicing disengaging recently).
Well, my problem is that whenever I try to tell my SO that a certain rule has been broken, let's say SS didn't wash his plate, SO will lash out on me. It's not that I shout "Your bloody son didn't wash the plate again!", I simply say "SS left his plate". Still, my SO's reaction makes it seem that I'M the problem.
For example, SS never used to say "thank you" after a meal, even though he never helps with meal prep. SO insisted he'd say "thank you". And he did for a while. Then he stopped. I asked my SO "So, SS stopped saying "thank you"?” And he lashed out "What are you trying to say? Why are you bringing this up? What's the problem?" The problem is I’M the one making the meals, so why am I being taken for granted?
Also, because of his obesity, SS is required to stick only to the meals we make him (as the dietitian ordered) and use the stationary bike for a bout 40 min daily. Most of the time he does it just fine.
But every time my SO and I leave our home for a longer period of time, SS eats large quantities of food, even though we have a rule that he can't, and then denies it. Every time I try to bring it up with my SO, he makes me feel as I'm the problem. So most of the times we end up fighting about it.
Because I feel that every time I mention something about SS, SO get's supper offended and takes it really personally, even though I just stated a fact and wasn't hurtful or rude.
HOW am I supposed to live like this? Would counseling help? I'm tired of all the fighting and feeling like I'm actually the guilty party.