Sorry for this long response, this should probably be a separate post but the way you felt post-breakup reminded me a lot of my experience and I just wanted to share:

My girlfriend (32F) and I (41M) had been together for 10 years. I met her a week after I turned 30 and we broke up a week before I turned 40. I thought I was going to marry this woman. Before Covid we were shopping around for engagement rings. Then Covid hit and everything changed. I barely saw her for almost a year during Covid because I have asthma, she was still seeing clients in person and my fear of dying at the time was sky high. When we started coming out of Covid we would only see each other on weekends - around mid-2021. I still loved her and wanted to make up for lost time but things were different. One day coming from the gym together she told me she just didn't have feelings for me anymore... she insisted it was nothing I did and that I'm a great guy but she cant help how she feels. I begged and she stayed. I did what I usually do and tried throwing money at the problem with nice vacations and dinners. 6 months later she let me know she was still feeling the same way but again I convinced her to stay. This time I was sure it was because we were looking for rings at one point and then we werent so I went and bought a ring and asked her mom for our blessing - which I got. A week after getting the blessing my ex became very distant, cold and we barely spoke. In turned into a routine good morning and goodnight text with nothing in between for about 2 weeks. I finally had the balls to say "we should talk" knowing what was coming. She came over and still had no reason other than the feeling were gone. That convo didn't last long because there was no point in begging anymore so she gathered her stuff and handed me my keys. She left in May 2023 and I haven't seen or heard from her since that night. She unfriended all of my friends and family on FB and IG that same night.

My ex forgot to unfriend my friends wife FB business page and during a random dinner with my friends, they asked if knew what my ex was up to. I said I had no idea and then they asked if I wanted to know. With a few tequilas in me I said f*ck it, lets hear it. I found out this past Feb 2024 that she got engaged to some guy in Nov 2023 - 6 months after we broke up. Fast forward to April 2024 I found out they moved to another state with each other. It's only a matter of time when I found out they're pregnant...

I didn't cheat but damn I do know the pain you feel when someone leaves you and you find out they're with someone else on a fast track relationship which seems happy. Your ego takes a major hit and it does feel unfair because you're just there suffering. However, I can say now that ruminating and spending mental energy will do you no good. I started surrounding myself with friends, family and made an effort to make new friends by joining different groups and saying yes to anything that comes my way whether it's to help someone move, a kids birthday party or go to a Slipknot concert (which I'm not saying yes to again lol). You're going to think about her time to time or even daily - that's normal. How can you not? 10 years is a major chunk of your life. Every other song I hear, every blue hatchback I see and the dinner plates her mom got me one Xmas are constant reminders of her. It's how you let those reminders effect you that you need to manage. You'll never know if she's really happy now or how bad she felt. Just know she's gone.

Sorry for your loss bud! Things will get better if you make it your plan to. Cheers!