You haven't talked to your girlfriend about it yet. Its going to be a long time before the legitness of that site is an issue. If your girlfriend agrees to a threesome, she will have considerations. She may not want to have sex with an anonymous stranger off an internet site. She might want to know the third party in your menage a' trios , or she may have a particular woman in mind. She may insist that the threesome be MMF rather than FFM. Or she might insist on an MMF session before an FFM session. There are lots of possible considerations that you need to clear with your girlfriend before signing up for some website.
Your girl will have an easier time meeting women than you. Add that to the list of reasons why you should talk to your girl first.
