I think you should end the relationship because your boyfriend sounds abusive. In addition to that, he has another grown man in YOUR 1 bedroom apartment. 

It's not your last solution. It's your best and only solution. This guy is verbally abusive. You deserve better.

You don't deserve to be spoken to in that manner, AT ALL! You are a good woman enough to allow his grown ass son live with you! Your boyfriend is no man in my eyes and I'm disgusted that he spoke to you with such hatred! He has zero respect for you and doesn't see you as a someone he cares about! 
 

Please kick this man out before he causes anymore verbal abuse to you! 

hell no. The MOMENT he yelled at you, insulted you, and threatened you, the relationship should have been over!

Anyone who calls you a stupid bitch and tells you not to discuss life problems with anyone, is not an asset to your life, not at all.  Please don't put up with this abuse any longer. 

Last solution? Kicking your boyfriend's ass to the curb (accompanied by his son) should be your first solution. No one who called me a stupid bitch and did not take my concerns about his kid in MY home very seriously would remain long as my boyfriend.

I mean this genuinely, not trying to be snarky - OP, you can benefit from some therapy to figure out why you are allowing this man to treat you this way. The son in the living room is not the problem, it's a symptom of the problem. How can you love someone who calls you a stupid bitch and doesn't care about your feelings? This is not a healthy relationship - son in the living room or not.

Forget the letter, get this jerk out of your life.

This is not the relationship for you.

After reading thrrough your posts and reading that this man called you a "stupid b*tch", my view is that ending this relationship is your BEST solution.  Your BF is abusive. Please don't think you have to take it.

i am sorry to read that you are living in such terrible conditions.  Ultimately, you know the choice is you can continue to live with abusive jerks or you can move on with your life.  Your partner doesn’t sound likely to change - letter or no letter.  You are doing some serious mental gymnastics to avoid the truth that this relationship is abusive.  He isn’t going to wake up on day with a different personality.  The question you have to ask yourself is why you are so afraid to lose this relationship ?  You stay because you get something from it - material and/or emotional. From the outside it sounds terrible - but your post suggests that you don’t want to lose it.  You might want to figure that out and make sure your reasons are valid.   

Bf told you not to tell anyone about his son. Are you afraid of bf? Get them both out. One bd apt.??? How can you have any privacy?  Why r u hanging on to this relationship? 

Your home should be a sanctuary. 

I have a rule in life: anyone who calls me "bitch" or any other insult is dumped and the relationship is over. He doesn't respect you, get him out of your life. 

Kick them out! What kind of grown man moves his adult son into his girlfriends apartment and then calls her a bitch when she (very rightly) complains?Dont let yourself be treated like this!!

Please take the great suggestions above and kick them out. How dare "BF" abuse & intimidate you like this?!? What an abusive, entitled, raising-a-dependent-Man/Baby *sshole!

If he respected & loved you, he never would have abused your kindness & generosity, or allowed his grown-*ss son to VISIT & be rude, no less invade your home 24/7/365+COVID-19. What a nightmare!

It seems like us anonymous StepTalk strangers have more respect & concern for your well-being than jerk BF. I hope you overcome your intimidation and tell him it's over & to move on out & bring his cling-on son with. You don't have to live like this. 

With concern, 

This asshole ended this relationship when he called you a "stupid bitch".  Have no qualms or regrets, put both of these idiot man-child morons on the curb and wish them well in the homeless community under the local overpass.

Please, value yourself enough to not tolerate anyone who would call you a stupid bitch.  Particularly a person who is supposed to be your equity life partner.

I could not imagine my father referring to his wife as a stupid bitch (mom would take a cast iron frying pan to his skull if he did) nor my brother using those words with his wife.  And there is not a snowball's chance in hell I would ever think those words on reference to my wife much less say them to her.

It is not the last resort to kick them out, it is the only resort if you have even a modicum of self respect.

smh

Don't write him a letter. Get a lawyer, call two men and a truck, call the Sherrif and move their shit to the local homeless camp. Then rekey the locks.  And don't forget to buy a gun and be ready to use it to protect  yourself from this trash and his shallow and polluted gene pool.

"And you better not talk to anyone about my son either. Don't you dare."

Or else what?  This is how domestic violence begins.  His abusive personality is pervasive and will affect every aspect of your relationship.  Run.

If you're having a hard time finding the courage to leave the situation, get yourself to a therapist to help sort out what's stopping you and to come up with a plan. There's no shame in that, and it will help you find clarity and strength.

My DH would be my exDH the minute he call me "stupid bitch." If you can't talk to your own partner about how you feel about something, you're in the wrong relationship. Get out of it so you can find someone who truly loves you. What you describe is far, far away from love.

Pack their stuff, leave it somewhere that they can pick it up and change the locks.  Block him and be done.  Those are his true colors and from here, you aren't going to get a fair shake.  I'm not dealing with exactly the same stuff, but similar.  If you aren't allowed to have an opinion about the stuff in your life and home without verbal abuse, it's time to cut your losses.  (Yes, I know, follow my own advice... so I sympathize with you not already being gone.  Leaving someone can be complicated when it's just in your head.)

Merry's advice above is solid, because a therapist is a great idea.

Best of luck.