I have to laugh at how the OP was about stating your gender and orientation in your posts, and everyone just went ahead and posted it in this thread. I think it's a good idea to have an optional info box on registration / profile edit for orientation, as well as some info on your partners.
I'm going to go ahead and be annoying by saying that while it would be useful to have this information when someone new posts, it's not necessary in order to provide some basic advice. Tailoring your advice because of someone's gender and orientation edges on "giving specific advice to someone you know" as opposed to "giving generic advice that applies to anyone." The former is only useful if you actually know the person, the relationship, and the specifics... at which point "I'm a straight female in a heterosexual marriage" part is already known.