I'm frustrated

My fiance woke up with a fever (100.5) we have a 1 year old. And it bugs me because his dad invited him to come over today. He called his dad and his dad told him that it's ok for him to come over anyways because my fiace has been wearing a mask and social distancing (he hasn't from his dad,mom,sister,niece,nephew, his dads gf). They are fine but it bugged me because he said he might go down there anyways. I told him that he shouldn't go. And he asked why. My tone went up a little bit more (I have anxiety and I try to not be extreme but it happens sometimes) and I said because even if your dad doesn't care, you should. He is old and his gf is basically living with him and she has a 2 year old. And if his sister goes over with her kids, think about them and they are around your mom who has diabetes. He made all these excuses and said he thinks its something else and not covid. I told him he should be safe instead of sorry. He got mad and said , whatever . I don't need this and your negativity and went to the room. I had to use the restroom to get my things because I'm going to quarantine and research about what I can do to sanitize my home and help my family and get tested. Hes watching a movie which we were supposed to watch but he watched it out of spite (I just had to add that petty thing because that does bother me, either way its not going to happen if we have to be in separate rooms) and I tell him that I'm not going to sugar coat things and he needs to think about his health and his family and he got mad and said just stop talking. I heard what you said. And what hurts too is that he goes and calls his family and takes their advice, but I am negative? This has been an issue where he puts his family first so idk why I'm no surprised and I end up being the selfish , negative Nancy. I've been supportive, take care of him, do everything I can do to make him happy. If he goes to see them or changes his mind because they told him the same thing I did. It won't be the same. But I have to still take care of him because I love him..I'm sad and just venting