I secretly wish it was me with just one of them instead of the two of them.
Is there a reason you just want to be with one of them?
Because she's a really slutty girl, I'm sure it's her who's doing all the fucking.
I understand that poly relationships can be difficult to manage, but stringing them both along is not right. You should just be honest with them and tell them how you feel rather than keeping these feelings inside and deceiving them both.
I'm going to clean the house while they sit on the couch and watch TV.
I'm sorry you are feeling left out. You should probably leave a poly relationship if you're not happy with multiple partners. Maybe this type of relationship isn't for you.