I don't think that most "monogamous intruders" to polyamorous relationships deliberately do so with the intent for breaking up the polycule or with a "secret agenda". Many of them think they can make themselves be OK with polyamory because logically polyamory is ethical, and because most poly people started out monogamous so you think "maybe I was just brainwashed to think monogamy is the default, polyamory is fine".

And then you can fight with your own desires for monogamy internally, thinking "this is just my insecurity", "this is me being selfish" etc.

You could call me a monogamous intruder to my now fiance's then-polycule. But I did genuinely want to give polyamory a go. I thought it was unfair for me to expect him to break up with his partners, and I knew they made him happy, and I wanted him to be happy because he genuinely loved them. And I didn't want to make the metamours sad either. So I did my best to be an ethical metamour.

But I couldn't make myself fall in love with the metamours just because that would make things easier for everyone. For me, falling in love takes time and needs to be organic. So I was very prepared to give it a chance but I couldn't do it immediately.

And when you're demisexual and in love with someone who has other partners that you're not in love with, it does feel like you're not getting enough love or attention, like you're being sidelined. That happened to me when he was in America and I was in Australia, he would have sex with the metamours and I would want to have cyber sex with him, and he wouldn't want to as often as I did because he was already getting physical sex from the metamours. So it definitely felt unbalanced.

And it's not as easy to say "just date other people too then" because that implies that people are just easily replaceable and missing time with someone you're in love with can just be filled with someone else's time.

And dating someone else involves challenges of its own, like would THEY be OK with polyamory?

Now after getting together with my partner, he ended up breaking up with one metamour for reasons unrelated to me, and the other metamour died tragically. So we are now monogamous. We're open to seeing other people if the connections develop organically but we aren't going to actively look for other partners to "fill a void".

But I've told him that I would be very happy for us to be monogamous forever and that I think I am naturally monogamous. The reason for it is not because I don't think polyamory can be ethical, but because of how difficult it is to spend adequate amounts of quality time with multiple romantic partners, and how difficult it is to align future goals in life and responsibilities (ie finances, kids, buying a house etc) without there being some kind of hierarchy in the relationship (the people who own the house together and have a kid together are definitely going to prioritise their time and relationship together over a lover that they don't have these commitments and responsibilities to, and it's very hard to find a way to make that work in a way that doesn't make one of the primary partners feel like their partner is dropping the ball on responsibilities or make the new partner feel like a second class partner in the relationship). I've also noticed that the one time I had another lover myself, the NRE meant I did stop feeling as intensely and wanting to spend as much time with my fiance. And I didn't like that. I like feeling intense love and passion for him, because he's my best friend. I don't want a new lover to negatively impact how I feel for him.

So no I don't think that Janet was necessarily unethical when she started to get together with Keith. But the unethical behaviour started when she started deliberately trying to undermine his relationship with the metamours, and manipulated monogamous-privilege to make him prioritise her in public. And then continued when she tried to emotionally manipulate him to agree to marrying her.

But he was also unethical (using rough sex and anal as a punishment implies it was coerced sex which is a form of rape, it's heavily implied Janet only consented to painful "punishing" sex because if she didn't he would break up with her, and that's coercion).

I also don't like the idea that "naturally polyamorous people" get bored with only one partner. That's not why people should be polyamorous. They're not treating their partners and relationships with respect then, or as full people, but as entertainment. People aren't toys that you collect because having only one is boring.

Ethical polyamory is when you genuinely love multiple people and you want to express that love sexually and romantically with the full knowledge and consent of everyone involved.