No, because she does love me, just not in a romantic way. That's... platonic love? You don't know enough about our relationship to judge how she treats me on a day-to-day basis.
Unless you mean that my love for her is still not platonic. In which case I'd have to say you're right. I don't really know how to handle that, and all I can really do is keep my expectations in check, which they are.
Their situation and my situation are still different situations, intertwined as they may be. I can be happy for them and sad for me.
This thread was NEVER going to be supportive of this idea. For a start poly relationships aren't seen in good light here as most people don't get how they can exist because THEY could never allow it. They will always respond badly to situations like these. So when a poly relationship is almost always dismissed here as never able to work, what kind of feedback did you expect for this situation which is even less traditional than that?
Add on top of that your kinda listless tone in describing all of this. Now this could be down to your depression (which you have described more as the thread has grown) and might just be how you write in general, but add it to the aforementioned and people are assuming you're not taking care of yourself, that there's no self-love here, that you're allowing your wife and their partner to just dictate all of this and you're being strung along.
Nobody here has ANY idea of how you are treated by your ex-wife daily. They have no idea how you get along with their partner. They have no idea how you gel as a group, or how your kids are handling it... beyond your listless descriptions, which I'm sure you can see are not painting it in a good light.
Why did you make the thread? Were you aware of how this forum reacts to poly and other similar alternative relationships lifestyles? Are you aware if the constantly pretty awful dating and relationship advice people give here?
This thread was never going to be anything but the way it is now, and you have helped steer it there.
Even if this situation works out, even if all parties remain happy, loved, respected, and the kids are taken care of and aren't negatively affected, even then you still need to take better care of yourself.
Meds and therapy is a good first step. Being able to go to the gym consistently for someone like yourself who has struggled with taking steps like these is pretty big... but you need to look to your future too.
There are going to be three of you soon, three people who can help share the responsibility of the housework and childminding. And while you are the stay at home parent, they could both provide a little extra help to give you time to do things like learn a new skill.
I worked most of my life in dead end low paid jobs and I was miserable. My depression went mostly untreated and I just couldn't find the energy to better myself. It wasn't until a few years ago that I forced myself out of that rut and taught myself a new skill (web development) and now I can work freelance when it suits me and earn very good money.
You could do something similar, you should absolutely try to discover something you have an interest in to learn that can be applied to the working world but also something that will give you a sense of self-worth, something you can be proud of.
And as you work on your depression you will likely rediscover your own desires for things, including the desire to be with someone. It should be good to be on your way toward building something just for yourself when this happens.
I only you know for sure if the situation is stable for you, if it is though you still absolutely need to build something just for you. Something that, should you wish or need to be, you can use to support yourself, your children, and potentially build a brand new life on top of.
That should be your priority imo, for you AND your children. And if, as you have reasoned, your wife and their partner truly do support you, they will help you with this.
And, if they don't, if they are secretly plotting to kick you out as most people here are telling you, if they see you trying to build something they might still be supportive because it would make the eventual split easier for everyone.
Whatever you do, OP, do not just sink into this and become reliant on your ex-wife. Even if they will support you forever, that is not a healthy place to be for you.
The time has come for you to really push yourself to build something just for yourself, even if you end up staying there for the rest of your life, this is something essential all of us need.