All the gay males I have known in my life don’t seem to want to settle down, most just like having sex wherever they can get it, even if it means telling the other male they may want to settle down, then they get their fill of sex and then dump them.
Out of the entire bunch, one (1) has gotten married. Knowing very little about the couple, I said, "That's going to be a colossal mistake".
His "husband" was a con man who took the poor guy for a fortune, and they were divorced within the year. He's a decent guy, just can't make good decisions, and he'll be sorting this awful one out for most of the next decade.
Just my opinion, but I think that her friends like the idea of being married, a whole lot more than actual marriage. It's hard for a narcissist - particularly a flaky one like all of Mrs. WBill's friends - to surrender 1/2 of what they want, all the time. A marriage is a ton of hard work and a lifetime commitment, and worth every bit of it.