My boyfriends New cat

My boyfriend and I have recently adopted a cat 3 weeks ago and he doesn't want to have sex in front of the cat. Neither do I but when the time comes, I don't want to be waiting. We use to have sex almost everyday if not every second day and now we have adopted this new cat into our world his sex drive has lowered. His excuses are 'I don't want the cat to see us having sex' or 'I don't want the cat to hear us', or usual stuff like I'm to tired...etc. I don't want to blame our new cat but how can I make him hump me without worrying if the cat is lonely or if the car could hear? and quick question do you think our cat knows what's going on?