My 4 week old likes to sleep on his tummy?

So last night I kicked my husband out the bed so I let my baby sleep in the bed with me. I gave in and let him sleep on his tummy but right next to me. He sleep 5 hours. And he usually only sleeps 3 at the most. So I'm still mad at my husband so again he's sleeping on the couch and my baby is sleeping in the bed with me. Should I let him sleep on his tummy?? He's like so peaceful when he's on his tummy.I could play drums and it won't wake him. He is VERY gy so I could see why laying on his tummy would be comfortable to him. I have tried mylcon drops, probiotics. Etc. Btw he also knows how to lift his head. During the day he lifts his head and stares at me. So his head is pretty stronger. If that makes any difference in preventing suffocation. What do you think?