Aggressive puppy

I have a Rottweiler mix puppy, he was 4 months old on the 5th, we rescued him from a horrible situation. He's so great with me but he's horrible with my husband sometimes. My husband tries to play with him and he just gets so aggressive. I do the same things with him and he just plays right back. I'm really concerned because I'll be having our first child in September and I don't want my puppy to be aggressive towards the baby. I love this puppy but my husband and child come before anything. Any ideas on why he might be like this to my husband? Husband says if he doesn't start acting right we have to get rid of him and that makes my heart break. He's such a good dog when it comes to potty training and learning tricks. We've been moving this week so he's been having a couple pee accidents in the house but it's right by the door. I know those accidents are my fault.

*Edited to add*

Apollo (puppy) isn't aggressive to my husband unless I'm around. I don't work so I primarily take care of him. Whenever I go shower or run to the store everything is fine. If my husband gets too close to me, pets Apollo while he's sleeping next to me or tries to move him from in between us, that's when Apollo gets aggressive. And he's never aggressive to any other person or animal. He's bristled up at one dog but then they started playing and didn't stop for 3 hours 😂