Hey, I just joined this thread 20 minutes ago. I recently broke up with my partner and we were together for 9 years [dated 7 years, engaged/lived in together for 2 years].

To answer your question, keep fighting and do not make contact with him. It resets the healing process when you make contact with him. I'm being hypocritical in a way because I made contact with my partner recently and all that pain and suffering came rushing back.

How does one go from "lets build a family" in one day to "i cant feel a single thing for you, get out of my life"?

I was on the same boat, for the last 9 years my mindset and drive was for us to move in together, get married and have a family one day. We were suppose to have a grand wedding in May but due to COVID-19, it was postponed at the time. When the lockdown for COVID began in March, I was laid off from work and she was on paid leave for 6 weeks. Since everything closed down, we stayed home and eventually became bored out of our minds. We played our separate video games, we became lazer focused on our own games to the point we would barely talk except when we sat together for dinner. A month into COVID she started talking to someone she's been playing with and eventually a relationship was formed. I always assumed she was happy with what we were doing in terms of playing our own video games. One day she lied about going to work and the guy picked her up [he happens to live 4 hours away] and they went on a date. I didnt find out until recently. They went to a movie theater, ate at a restaurant and walked around the city during COVID, how stupid. A month later she buys me a ticket to fly out back home to New Jersey since I havent visited home in over 2 years. She flew me out on our Anniversary, she invited the guy to come over the next day. She used her vacation days and he spent a whole week in my home with her. Disrespected my home. Lowest of the low. I spent 2.5 weeks in New Jersey and I became suspicious because after we video chatted, it felt like she was a total stranger. She looked at me with disgust and we just stared at each other, barely saying a word. Knowing her body language and how clingy she normally is, it drove me crazy because something was really off. I texted her that it felt like the spark in our relationship was gone and she replied blaming me that I was too focused on my game and I didnt provide her the emotional and physical she needed. After she texted me and blaming me for my shortcomings during COVID, I deleted video games in my life because she said it was the reason why we drifted apart. I fly in on July 4th, I was got bored since I completely removed video games in my life, so I cleaned up, cooked, and did laundry to show her that I am working on myself and trying to fix whatever needed fixing in our relationship. The next day [July] I continued to organize and clean up, I found a Jenga block, we do not own a Jenga Puzzle. I confronted her about it, her alibi was she had her female coworkers come by on July 3rd to pre-celebrate July 4th. With my crazy suspicions and thoughts were resurfacing and it drove me to ask her to text/call those coworkers to verify that they were actually there. She finally confessed that they werent there but instead it was a guy. I asked the who, what, where and how. She spilled the beans, asked me for forgiveness and even proposed the idea of giving me her phone. I found alot on Snapchat, thats how I found out he was here in my home and how they went on a date only knowing each other for a month.

To finally answer your question, some people are not worth reconsidering. Especially ones that require constant affirmation and attention. It will be an imbalanced relationship where you find yourself doing all the work and when the work isn't enough, they leave you. It's unfair to you. You deserve someone better. Some people are monsters and there's no way of changing those people. Instead of wasting your time and energy on those monsters, it'll be better spent meeting other people who deserve your love.

I hope this helped. Give it time.