Newborn and stepchild

Ok so I just had my baby on the 11th (8 days old now) and my boyfriend’s son is 12 and he’s visiting us this weekend. I feel like I’m being a bitch, and coming across as if I’m showing favoritism because I’m so focused on my baby.

I can tell my boyfriend is getting annoyed because I tell him his son needs to wash his hands before touching the baby. I get nervous when he wants to hold him because he’s just so rough with him. But I try to sit back and let my boyfriend be the one to tell his son to be careful/show him how to hold the baby. Also, I want to tell him to stop kissing the baby but I don’t want to take away him being excited to have a brother.

I been with my boyfriend for 8 years, and his son is like a son to me but with this being my first baby things are going to be different.

Any step parents have any tips for me ?