I think there are two things here you need to address
First, therapy. You cannot see yourself as a 0 human being just because a dickhead like your ex thinks girls must be like a X actress. I am not making assumptions or being mean, your former partner is trash. I have been there like you, in fact, the reason I joined this forum and this community in 2015 was because my ex boyfriend left me when I was dealing with an horrible illness back then that made me loose weight and was constantly bullying me because I was not enough for him anymore. I ended up adding depression to my anxiety disorder and that was the last thing I needed to keep up with my life. But it happened. And at some point I did not want to keep going on and I did not want to breathe anymore. But, my parents, my sister and few friends of mine push me to seek professional help and here I am 7 years later - still going to therapy once a month, but feeling anxious is not as hard as it used to be and depression is gone. And my perception of life and about myself have completely changed.
We tend to compare ourselves with everybody. And that's something we need to stop doing even it may take some time to change the habit. Following up what happened in 2015, let me tell you this:
In fact when I was trapped in such chaos, I used to be super jealous about my youngest cousin - she is tall, athletic, super beautiful, smart and guess what ? she has huge boobs. But really huge boobs, 36E. I thought I had to be like her but heck I am petite, and my breast size won't be never 36 because I am super tiny compared to her shoulders. I was obsessed to be like her. I cried like 98765 times just because I knew it was not going to happen and got obsessed with growing (at 22 years old) and having a bigger décolleté.
When I found out this place, I was already working on my weight: I was only 42kg. No periods. Super skinny. People were making up rumours about me. My former partner (I call him Mr Psycho btw) kept telling people I was crazy and lost, so that was not helping at all to gain weight. But, with effort I gained some weight and I was able to bounce back my breast size. But I was still not satisfied because I KEPT looking to be like my cousin, so the frustration was insane. I was barely 32B and wanted to have at least another 4 cup sizes in 2016... I noogled a lot and all I got was 3cm in a year. You can picture the whole drama because I could not reach my goals.
So I was open about that part in my therapy journey - that I had unrealistic goals towards my body and I had such an anxiety because I knew I could not make it work or at least in a short period of time. SO I worked on that too, because self-esteem is a super complex puzzle and all the pieces must fit to be in harmony. It was tough, and nowadays after five years working on this, kinda sucks sometimes but I don't let my brain to bring me down just because I am 5" and I am not explosive.
What I am telling you is you need to be freaking honest and seek for help. Even reaching your NBE goals I don't think you will be happy with yourself because the human brain is a pain in the a$$ and as soon as you could have the breasts you desire you can easily pick another thing you don't really like about yourself and there we are again, back to square one.
You need to work on this honey. You cannot feel miserable about yourself.
The second thing we need to address here is: NBE can work, but you need to know what is missing in your body. We are not doctors here, but we know we are a bunch of hormones - especially women - and we rely on hormones a lot. On the other hand, this is about genetics too in my opinion. I think some people have better gens or more hormonal balance therefore they reach their goals sooner than others.
Luck or not, sometimes life is a rollercoaster. This is why it's good to take breaks and re-evaluate what is missing or what you need to do to feel better FROM THE INSIDE.
Take a break on this journey. Breathe. Seek for help. Work on yourself! And come back if you need so whenever you feel ready <3
PS: Last year my cousin confessed me she has self esteem issues. She is not happy the way she looks. She complains about her breast size and how difficult is to play sports (she plays soccer professionally) and being a woman. She receives lots of insults when she plays when the public is 90% male. She told me most of the guys she knows make assumptions about her and how harmful are certain comments.
I had no idea about this, and I feel sorry for her it has to be horrible to work in a male dominated work environment.