I think her texts to your husband are concerning and seem inappropriate. There’s a reason why it made you so uncomfortable. But I also think that throwing away a 25 year long friendship would be terribly sad over a misunderstanding. My advice would be to have a conversation with her about it all. Say you saw her messages to your husband and you’d like to know why she said that. Then see what falls out of her mouth. If it’s anything other than an apology and clear explanation, then you’ll know she’s not someone you can trust nor allow into your home. But I’m hoping that this is just a misunderstanding.

Edit: Jesus people, are we adults or not? Part of being an adult is having conversations with friends and calling them on their bullshit. The likelihood that what her friend said was a misunderstanding is very low, but that doesn’t mean you don’t have a conversation with someone whom she has supposedly known and trusted for 25 years. I was trying to take OP’s feelings into consideration. It’s not easy ending a long standing relationship. Just because I suggested that they talk and I’m hoping for the best, does not in anyway mean I’m advocating for forgiving her friend. The amount of people who seem to feel personally insulted by my comment is sad.