If her relationship has been going on with him for years there is a good chance that your friends and even family know already.
Welcome him in and respect that he is now the husband in the relationship. You could even consider a wedding ceremony where you give up you husband privilage to him...
I love the feeling of humiliation when Chris takes me shopping for panties. She holds the, up in front of me and makes comments like"These will look nice on you and your little wee wee should fit in them"