Just wanted to write out my situation because I find it therapeutic and maybe I might get some helpful tips. I will, of course, get some criticism but that's ok, it's the internet.
My MIL gets cold sores and has passed it down to all of her 4 children. I told my MIL that I don't want her ever kissing my baby (active or not active cold sore) and my husband agrees with me. My MIL doesn't like this rule and thinks that I am being ridiculous. Despite this rule also coming from my husband as well, she thinks that it was all my doing. My husband has decided upon himself not to kiss our baby because he doesn't want our daughter to ever get cold sores as he knows how upsetting it is to get them. My husband gets them frequently whenever he is stressed out and it really bums him out. He is fine with not kissing as he knows he can show affection in other ways (hugs, etc.). I come from a culture where we don't really kiss but we have other ways of showing affection, so I don't think my baby will miss out on much by not being kissed by her grandma. I also think that my daughter would much rather prefer to have my rule than to risk getting a cold sore. I personally would be upset with my mother and grandma if I got a cold sore or any illness that was passed down by my grandparent because my grandparent insisted on kissing me, therefore, I have stood by my rule. I obviously can't protect my daughter from everything, however, this simple rule can definitely help reduce the risk of getting a cold sore. Considering my MIL gave cold sores to all of her children, I know that it would be likely that she would pass it to my child if I didn't have this rule.
Despite all of this logic, she thinks that I am being unreasonable and she has told many of her relatives about this. I know she has talked about how "unreasonable" I am to others as I notice her side of the family acting differently with me. I know they all think that I am being overprotective, unfair and maybe rude, however, I wish they could realize that just because a baby is cute that doesn't give them the right to smother them with kisses. My baby can't speak for themselves at this moment, she can't communicate if she doesn't want a kiss or doesn't want to risk a cold sore, so until she is able to do so for herself, I am going to make decisions for her. At this moment, I feel she can live a happy life without kisses from her grandma, because I know I was able to. I also find it frustrating that my MIL tries to push her parenting ways on me, every time I explain why I am doing something a certain way she questions me further about it. Why do I have to explain myself to her?!... I like to parent according to today's evidence-based research /recommendations, however, she always tries to mention that things they did before were okay and she ends up defending the way she parented. Ugh, why can't relatives just back off? They had their chance to parent, let others have the opportunity!