😱 during sex!

My bf of 2yrs has no sense of privacy. Whenever I am at his apt I feel no privacy. His bedroom does not lock, his bathroom also does not lock. He has a 4yr old daughter. She's adorable and cute! I do not mind her at all. She does have a bad habit of sleeping on her fathers bed instead of her own. I recommended training her now to get used to her bed bc it'll get harder as she gets older. I suggested that a lock would prevent her from waking up in the middle of the night into his bed. She would have to knock so u can open it for her. Also bc his bedroom does not lock she constantly walks in on us during sex. This happened about 10x already. When it happened the 2nd time I asked him to get a lock. I even offered to buy him one. His reponse 
Him: I dnt want to lock my daughter out of my room. 
Me: so you're ok exposing her to sex at such an age?! 
Him: I'll teach her to knock before she opens the door 
The knocking didn't work and he said he'd have to get a lock. He still has not and it has been a year...
Anyways at the beginning when we were having sex this one time we were making out like crazy, cloths came off and then he said he needed to go take a dump. No problem I said I'd wait. He comes back and we continue what we started. I was on top first and then we rotated and he got on top. After that he picked me up and then he looked on his bed and goes "wait was that u?" I looked and it was something brown on his bed. I said no what is that bc Im not on my period. He sniffed it and was like it smells like poop. R u sure that's not u bc u were sitting on it, ur butt was in that vicinity. Seriously I was annoyed at this point. I said babe u jst went and took a dump, I haven't took any dumps yet today. His face turned red and he said omg that's so embarrassing. I played it off like it was nothing (should have sent him to the bathroom to wipe his ass). 
On Monday we had sex and there it goes again, another brown stain after he took a dump. This time it was a bigger smear! I couldn't believe it! He's almost 30 and doesn't know how to wipe his ass?! He was so embaressed again and laughed but this time I was disgusted and shared with him a few methods that I use to wipe. I even recommended using wet wipes to make sure he's clean. 
Today is Friday and he still has not changed that bedsheet. It is still on his bed as if there's no poop smear on it. I am beyond baffled at this! He called his ex a dirty "sucio" slum but I'm starting to wonder if it was really her or him. He also called his twin dirty when he was with his ex wife but I'm not sure what his definition of dirty is anymore. 
I also asked if he could use the poop stain to his advantage and tell his daughter that his bed has poop bc maybe that way she will stop coming to sneak into his bed at night and he said no that's embarrassing bc then she'll go tell everyone that I pooped on my bed. I told him to jst deny it then and tell ppl that it was the only way u can teach your daughter to sleep on her own bed.
Is this something you would take in your relationship? Or is this the clue to leave? 
UPDATE: thank you everyone! I'm still there bc I dnt know what to do and I thought maybe I should sit him down and have a convo with him about it first to give him a chance. I love him but I am starting to have doubts. What about the lock issue?Â