My experience is that bi-gender people tend to be very isolated from other bi-gender people: bi-gender isn’t a well-known or widely used gender identity. I have yet to meet another person who definitively identifies as bi-gender face to face, even though I’ve met many other people who identify as nonbinary and have connected virtually with dozens of other bi-gender people. For other bi-gender people, the gulf may be even wider. That’s why we’re lucky to have at least two supportive and well-established bi-gender communities (and if there are more, please let me know so that I can list those as well)!
The first place I found online to connect with other bi-gender people is bigender.net (no hyphen). This is an old school online forum, and while the interface isn’t exactly up to the minute and it’s not swarming with people, there are always at least a few long-term participants available to connect with. The forum format makes it possible to have extended, in-depth conversations. I’ve met several good friends on this board.
By the way, if you join, don’t try to later log in through http://www.bigender.net without the /forum at the end of it. The home page for the site is for a journals feature that uses a completely different login system and is slated for retirement.
I’m newer to the second community, but it’s a lively group of Facebook users called Bigender Support . Here too, members are strongly supportive and worth getting to know. You don’t have to be bi-gender to participate; the group is for both bi-gender people and allies. It’s a closed group: you must apply first to participate.