Me and my boyfriend disagree on people kissing the baby, should I give in??

This is a hard topic for me, the son of my close friend got herpes at 15 months old from a relative who kissed him on the cheek. He had some problems with his central nervous system because of this and was in the hospital for a while, he’s 4 and still breaks out in sores. This relative didn’t have an obvious outbreak and never knew she had herpes!

Because of this and other possible complications with kissing babies I talked to my SO about only us kissing him as we’ve both been tested. He is having a really hard time with my mil not being able to kiss our son and it’s a weekly argument. She also sneaks kisses when she thinks I’m not looking. She’s already given my son a cold and pink eye, he’s only 4 months old.

He says it’s in his culture to kiss babies (he’s Peruvian) and makes me feel like I’m taking something from him. His whole family thinks I’m being dramatic and controlling.

I’m at a loss and don’t know what to do at this point, I don’t know if I should keep pushing or just give in...