Hello all, I'm gay and I am assuming my partner is too, otherwise things would be pretty awkward! :-P All Kidding aside I think for the most part, financially speaking, there aren't too many differences between gay & straight couples. The big ones that stick out in my mind would be:
1-Gay male couples would most likely earn more than straight couples (and both earn more than lesbian couples).
2-Having a kid for gay male couples can have a lot of upfront costs in terms of adoption or surrogacy.
3-Lastly, I read an interesting article a while ago about gay folk who grew up in small times are more likely to be successful then their fellows. This was theorized to be because they have a motivation to leave their (often bigoted) small towns and the drive to succeed once they reached a more metropolitan area! Wish I could find the link...
None of the above would particularly lead to a more mustachian lifestyle. I have been fortunate to surround myself with friends who share similar life choices. Even before I met my partner I only really dated very frugal gay folk. Whether gay, straight or anything else it is good to share a similar lifestyle. Thats my 2 cents anyway.