He won't stop. What to do?

One night my husband and I decided to have sex. Our pit bull was in the living room, but our door was open, so he could see in if he looked over. We didn't think anything of it... It was the worst decision ever. We started having sex, and my husband was on top of me, and thrusting into me. The next thing we know our pit bull rams into the door, hops onto the bed, and tries to mount my husband. He has never done this before. He didn't know what humping was. It took both of us to pull him off. Ever since then, he has repeatedly tried to mount us even if we are not having sex. He tried to rape our weenie dog who ended up biting the pit. He even taught our weenie dog who is neutered how to hump because we caught him trying to hump our pit bull before. We have tried so much, and nothing is breaking him of this habit. We don't have sex in front of him anymore. I tried hugging my grandma today, so I had to bend over because she was sitting down, and once again, he tried mounting me. Ugh. What to do.