Why on earth you want to "change" yourself?

People want to "change" themselves all the time. Work out more, learn a new language, quit drinking, etc.

Also, I have no idea why, but this community loves to gatekeep who can and can't be NM. If she likes the idea of it but struggles in practice, who are you to say she's monogamous and that she's deluding herself. There are absolutely coping tactics for feelings like jealousy and insecurity.

As the other person rightfully pointed out to you, monogamy/non monogamy aren't immutable aspects of ones self. I lived my entire life as a monogamous person... until now. I would not have been ok with it before, but I am now.

I am not saying it, SHE IS.

She's also saying she wants to be non monogamous. That the ideas make sense to her, and that she wants this to be the way she lives her life, but she's struggling with feelings she didn't expect.

The only solace I can offer is that it will end at some point and there will be another point further on where you look back on it as a positive thing. I know that means less than nothing right now but something that's gotten me through a lot in the last year is understanding that it's ok to be sad after making the right decision.

I would also humbly suggest maybe thinking about talking with a therapist. Breaking up is never going to be easy but the extra support wouldn't go amiss, plus the way you talk about your relationship is...it shows some potential issues.

Love is wonderful, sure, but talking about how badly you want to give and receive love, about how it felt like a drug, wishing he kept stringing you along - these are things that are characteristic of someone who has a preoccupied attachment style and is acting that out in their relationship. If you zoom out a bit on what you said, you're wishing that he mistreated you. You're actively wanting to be treated poorly so you can continue to feel like you're able to give and receive love.

That's not a super healthy dynamic and it can lead you into accepting relationships with people that are not good for you but you'll do it because you want to feel like you can love and be loved in return.

I struggled with exactly the same thing. I was accepting any connection I could find with someone else if it meant I could give love to them because, in my head, I was only worthy of receiving love if I gave it and because I was so desperate to be able to give love I ended up giving it to people who were not capable of returning it or I gave in a way that made them unable or unwilling to return it. It meant I ended up dating a lot of narcissistic people because narcissistic people love to take and know how to give just enough back to keep you on the hook.

It's a lot of work to do but it changes a lot about how you relate to yourself, your past, and what you want in your future. It won't be comfortable but you'll learn things about yourself and grow in ways you never thought you would.

The book "Polysecure" is a really good starting point. It focuses on non-monogamous relationships but the core of it is attachment styles and how to develop a secure, stable relationship. It's really good even if you're a mono person (and no, it won't "make" you non-monogamous.)