Having a hard conversation

I’m really reserved with my feelings and I really don’t like having hard conversations but I’m so annoyed that my boyfriend’s parents took our 2 month old baby to church today when he stayed the night at their house last night. I didn’t want the baby out around anyone, it’s pretty much still a pandemic & ppl still are catching covid. I don’t even take my own baby out in public places except if I’m running a quick errand. It’s bad enough that I’m missing my boyfriend getting sworn in tomorrow just for that reason ( I don’t want our baby out around crowds). I’m going to mention this to him but what is the best way to bring it to his attention?