How to deal with toddler tantrums for parents

I’m looking for resources (ebook, YouTube, websites, etc) on how to deal with toddler tantrums. I follow the Montessori method and I don’t agree with putting my child in her room while she’s having a tantrum. My husband on the other hand has a hard time dealing with tantrums and he threatens her with time out and other consequences instead of staying calm and trying to help calm her down. I’d like to help my husband learn about dealing with tantrums using a softer approach.