cat pee smell in my home at random times but cats aren't peeing in the house
So I've lived in my home now for 2 yrs and never had a problem with a pee odor or any odor of any kind. I have 2 cats and they are very clean and litter trained and keep their boxes clean everyday. Just two days ago my boyfriend and I were in the living room and were overcome with a very strong odor of what smelled similar to cat pee and since I've never had this before, I lit candles and investigated the house over and never found anything with that kind of odor. I even smelled all the furniture the wall bases and carpets and nothing! So I let it go, the next couple days I didn't smell it anymore until last night. I smelled it again! Now, I know that if an animal is peeing in your home, you are going to know it and I have mild ocd so I KNOW my cats aren't peeing anywhere. This smell just started and has never been before, what the hell is it?