Sorry, but as a queer Arab I think you’re completely off the mark here. Gaza is a literal concentration camp. People are burning alive every day. What LGBT+ people in the USA could go through under Trump is very bad, but to think it comparable is delusional.
My gf and I are poly. She has a gf. It doesn’t bother me at all. You should talk to your husband; his resentment isn’t necessary. It sounds like everyone (your daughter, her bf, his gf) are all aware of the situation and consenting. What’s the issue?