@Kat1,
I bet your landlord will have something to say about so many guests.
And it might not be him/her embracing these extra folks on a regular basis with open arms.
If you need to, make the landlord the bad guy. "Oh, sorry, but our landlord only allows five nights of guests per month!"
And talk to your housemate and explain that this is not the relaxing home you had envisioned for yourself. In particular, life with teenaged boys can be stressful, messy, and stinky. Do they clean up after themselves? Pay their share of the utilities? Because if they don't, then yeah, this is really unfair.
You can go to a more nuclear option and have it put into writing, e. g. the boys will buy their own laundry soap and dish soap and do their own chores. If they don't and the house becomes infested, then the cost of an exterminator is on them (don't be so quick to dismiss this as a possibility; roaches love unwashed dishes).
But no matter what, you both need to be more assertive, or these guys will take over - and it sounds like it has already started. Good news for you, though, if push comes to shove, you can just leave. Plus you've got a job and can save money to get your own place.
In the meantime, roommate disputes can be hell on earth, but if you don't learn to stand up for yourself here, where you don't have a lot at stake (if this guy and his sons start to hate you, then who cares? If they become destructive, then call the landlord or the cops), it'll be a lot harder later in life when there's more on the line.