Go size down, I purchase S but its very loose

This jumpsuit is extremely comfortable. But unfortunately, I don’t think I could wear it anywhere but around the house. I don’t mind showing cleavage at all, but the top part comes completely open as you move. So I can only wear it at home in front of my husband because he doesn’t mind the free peep show. I’ve tried to pin it, and it does work ok. But it’s just too inconvenient to wear it out like this and I don’t have a black pin so it looks ugly. Overall, pretty disappointed. But at least it’s comfy to wear around the house.