Welcome to our forum.
I hope you are able to find all that you seek in the polyamorous lifestyle. Check out the "Dating & Friendship" boards if you haven't done so already.
There is a lot to learn about poly, so take your time and read some of the many threads on this site. Don't hesitate to post if you have a thought, question, or concern.
Sounds like you have a good relationship with your MM. I presume his wife knows about the situation and is okay with it?
Glad to have you aboard.
Love means never having to say, "Put down that meat cleaver!"