I agree with Lilpiggietoes and say, don't go. No "white washing" it. I understand your husband wanting to continue the relationship and he can do that by getting together with his friend without you. The women don't need to be involved. If the friend isn't willing to change the way that they get together perhaps it's time to let the partying go while still maintaining contact via phone and e-mail.
If I were your husband, I'd find a way to compromise with you and them. And he should be more willing to go along with you then with a friend. Is he not concerned about the money?
Actually,if I were him I'd also want to save money and stop the partying. Friends continue to be friends as they mature together. It sounds like this friend is not growing up and so I do wonder why your husband wants to continue being immature with him.
What I'm trying to say is that to last, friendships need to be about both people's needs. I suggest that it's time for your husband to evaluate the friendship. If he enjoys the partying then he should continue doing it but he should understand and accept that you don't enjoy it. Your not going shouldn't be a problem.
If he doesn't enjoy the partying, I suggest that it's time for him to stand up for himself, you and your relationship, as well as his interests and plan a get together that meets his and his family's needs. Friendship goes two ways.
Perhaps the other couple could come to your house. That way you can limit the drinking and have some family fun. Play board games with the children or put them to bed and play cards or watch a movie without the kids. Show them that activities can be fun without so much alcohol.
By doing this you're also finding out if they can be flexible and consider your needs too. Why would your husband want to get together with someone he has nothing in common with and who aren't willing to try out a different way of relating?
You can't change anyone else but you can be true to yourself and your family's financial needs.