Secondly...

Hello again.
There were a few elements in the last post that I left out, because it needed enough in depth explanation that I felt that it deserved its own post.
Like the complexities of the polyamorous relationship and what it means and does not mean.

First of all, it isn't cheating. Cheating is a dishonest practice in which you have more than one lover without the permission of one or more lover.

It is not swinging. Swinging is having multiple sex partners without having multiple relationships. This is generally agreed upon as an acceptable behavior.
I just read the term polyfuckery, which is when one claims to be polyamorous, mostly to get into bed with other polyamorous people, and without any sort of emotional bond.

It's not a three-way. That's just sex.

It is a relationship. And if you've ever had a relationship, you should know what that means-- all the drama and crazy and emotions and feelings and communication necessary. It's nuts.

There are many kinds of polyamorous relationships. In ours, it is a triad. This means there are three of us, all of whom are romantically involved with the other two.
In our case, it means that there are four relationships to maintain at all times.
J+M; J+MB; MB+M; J+M+MB
We've established that there should always be open and honest communication between all three of us. One of the rules I've found someone else stating is that if you don't want to tell your others, you should tell your others.

I think the biggest source of confusion to people that have not seen, nor participated, in a polyamorous relationship feels that it's not a relationship. Especially in the cases of hinged relationships (where one has two partners who have nothing to do with one another, also called a V), or N where there are four people who have two partners each, and I'm sure there are people who have some W going on or a hell of a fork going.
And personally, I think that's much better than cheating, or affairs, or serial monogamy, where you dump one and get a new one  the next week because the shiny wore off.

I've only had one relationship before, and that was monogamous and always long-distance, so I admit I'm no authority on anything romance. In fact, that's something I'm rather enjoying about the polyamory with the partners I've chosen-- there are two of them, with two very different styles and tastes and I can test out what I like and don't like with each of them. He's very much more sexual and energetic and dominant, whereas she's sensual and passionate and doesn't take command so much. The only problem I'm having so far is that I'm a sarcastic shithead, and I'm meaner than I intend a lot.

M and J are engaged to be married, eventually. There's been talk of semi-marrying me (no legal, obviously, but I could write a will to allow them to make my funeral and hospital decisions), but as aforementioned, they're the priority, until I am more established in the relationship.
However, I'm no less committed than they are, and I have no intention of bailing on the relationship, either. I am Second Wife only because I appeared second.
It is a valid, real relationship. It will have all the dynamics of one and more because there are more elements at play, with more pieces and players and thoughts and feelings.
So wish us luck. We'll need that.