Is this weird or am I crazy?

My husband talks to his cousin all day everyday (despite promising me he'd chill it out and that only lasted 2 months). She is always sending him pics of her outfits in which he always says she's beautiful or if I'm close by he will reply with "Nice". Whenever she sees us she runs up and hugs my husband and only talks to him. Despite me saying hi and I got completely ignored. He says their best friends but I feel weird around them and uncomfortable. This girl Hates me for no reason :( . At a point she messaged my husband saying she couldn't handle me and wants nothing to do with me and would like to only be close with my husband. She said we didn't have to talk. And I felt that was to far and out of line. So I had my husband choose between us. He hesitated but choose me. They lost contact for months and finally she budged and messaged him sorry and he instantly forgave her and and didn't tell me about the messages until later and told me he will do whatever I want him to. But that he wanted to talk to her at least once more and how much he misses her. Well I got in a super bad jealousy rage and broke his phone. I felt like the worst person ever so I gave in and told my husband I was sorry and will do whatever he wants. Well we recently hung out with her. And she just ran into his arms and I felt instantly uncomfortable. Idk what to do. I don't talk to my cousin all day everyday. I most certainly wouldn't do it on days that are important like the day I got married or updates on my baby while my wife's in preterm labor and this cousin has already been mean to said wife who is in a state of distress. I feel jealousy with her and I wish I didn't because I know it's weird. I'm at a point where I'm questioning reality if I'm crazy or it's them?.