How to break swaddling help!?

My 7 month old son won't sleep at night unless he is swaddadled! (One arm only) I leave his other arm out so he can sleep on his side while snuggling his puppy. During the day I can get him to sleep without it if I can rock him to sleep then lay him down. He's really good at putting himself to sleep, but at night it's a whole other story! Even if he goes down first, he won't stay asleep until I swaddle him. Should I just go cold turkey with it and endure a few sleepless nights? Help!!! I feel like he'll never be able to sleep without it!