Welcome! Definitely take a look around, do a tag search for 'triads', 'unicorns' and all of that. If you want to meet up with more poly people there is a yahoo group for Michigan poly. They have monthly meetings, lunches, game groups, and informational things. Mostly down south near Detroit and Plymouth but we've made it a couple of times to a game night and had fun!
You will get a lot of eye rolling with the idea of 'adding' someone to your relationship and I really urge you to give it some thought. My husband and I have been together more than 20 years, married 19, are in our late 30s and it's just never occurred to us to 'add' someone to our lives. Our relationship is ours. Now the one I have with my boyfriend is ours as well! When you date, you kind of want to get to know the PERSON you are dating so one on one typically works best.
Me: Late 30s pansexual poly.
DH: My husband of 19 yrs and father of 3 teen girls.
DC: LDR of +4 year