No, you aren't.  Tell him yourself. "SS, I really need time to myself when I get home from work. Could you please use the downstairs room for what you are doing?" If it hurts his fee-fees, so be it. Your husband cares more about your SS's wants than your needs and it won't ever stop unless you stand up for yourself. 

If they're there every.single.weekend when do you and your dh have couple time? Don't you ever have a weekend just for yourselves? Why does your husband even bother having his sons over if he does nothing at all with them? 

If I am relaxing in the living room and SD10 keeps poking around - I def let her know. I'll say "_____ I'm trying to watch this show. It's not appropriate for you (The Bachelor, for example) can you take it upstairs?" 

I guess our difference is also that DH doesn't have a problem telling SD to scram. Sometimes he will watch sports in the basement, but it's hard for him to enjoy when she is hovering around, talking to herself, saying "hey dad, look at this." 

No, you aren't a monster for wanting to spend time in YOUR house other than your bedroom. I've read a lot on her that many SMs just retreat to their bedrooms when SKs come over. I refuse to hide in my own house!!

Firm and consistent, polite request to your SS each time.

Firm and consistent polite response to your DH each time.

How did you date if he has his kids every weekend?

So, let me get this straight from what you wrote OP, he isn't even spending time with either of the boys and is enjoying his solitude but makes YOU feel guilty for asking for the same thing???  F that. Send SS to his father, send him downstairs, send back to BM, anywhere but where you are when you get home.  Geesh, sounds like you live with a bunch  of male babies in various stages of adolescence. All three of them.  
 

I might even take next week for myself and stay far away from DH. Just tell him you are making up for solitude denied to you all weekend.  Then hand him the lotion and some tissues.     

To his BF.  Let him bother him.  Why have SS every weekend if there BF does nothing with them.   .?

Wait---WHY does your dh have them every weekend?

I think that the way our husbands treat us that help build all of that resentment. It gets to the point where you don't really care about whag happens. If your husband is constantly taking their saide or making a bigger deal of little things, it's not right. If it was your kid and you told them to go to their room would it be a big deal? I just hate the feeling that we are left that we are horrible people. It takes a lot to come out of that. Thir guilt makes them act in irrational ways and we don't have to carry that guilt for them. I have been married for 4 years and things like that have always been present. I always feel like I'm a horrible person and I always second guess myself now. That was not like me before. My husband has recently been more open and aware and has apologized for some of the things that have happened. It didn't happen until  we were really close to splitting though Keep asking for your needs and dont settle. Your feelings are valid.

SS gets to spend all day in the living room while you work. It's absurd to question yourself for a second that he go to the basement so you can have some time to unwind after work by yourself.

I would tell DH if he is so worried about SS and his delicate feelings, when you get home from work, SS can go upstairs and hang out with him. 

I agree with maybe sending him to see his dad upstairs.  Are you able to just ask the kid w/out it getting to dad?  Sometimes you just have to bypass these morons and go straight to the source.  I've seen it time and time again that often the skids will listen if asked directly.  Problems arise when SM asks their dh to intervene and ask for them.  If it bothers you, then you should be the one to be able to talk or ask them directly.  It doesn't bother the dad, so making him ask often just ruffles these delicate pansy as* mens feathers.