My partner is still friends with a couple of people she used to have sex with. They're ten years younger than me. I don't care about that sort of thing in the slightest. In fact, I'd be happy for all of us to get together and do a reunion special.
I started dating my missus when I was fucking someone else. Wasn't really a relationship (with the other girl) but I never broke it off either way. I didn't ghost her or anything. I just stopped calling. Years later I ran into her and there was no bad blood but she did mention the fact that I just disappeared one day.
As for my ex-wife, I didn't speak to her for nearly 10 years after she broke up with me - over the phone - from the other side of the world. Now, I wouldn't say we're friends but we're on good terms. I'm happy that she found someone and had kids of her own (although he killed himself last year so that sucks) and I think my ex-wife is happy for me... although I wonder sometimes if she regrets leaving.
I've never understood why people mourn relationships for so long. If someone doesn't want to be with you, that's it. It hurts sometimes, but it's not the end of the world. There are other fish in the sea... It's different if you have kids. That massively complicates everything. Often, it's impossible to completely remove your partner from your life in that situation. You still need to interact with each other if you're raising a child. At least, you do when the kids are school age anyway.
But no kids, fuck it.
I've been there, though.
When my first marriage first broke up, I didn't want to accept it. I was angry about it. It felt like I wasn't in control of my life. Somebody had pulled a switch and an air lock was slowly opening. All of the useless shit I collected throughout that relationship, lining our shelves, starting to shift on the spot slightly. Then things are airborne. Memories are unravelling. Priceless words are losing value and becoming unfamiliar. Flaws cease to be charming. Things are said that cannot be rationalized. It was ugly, but I kept holding on long after that. Long after she was gone. Holding on to nothing in a house full of cardboard boxes.
I used my relationship as an excuse to abuse drugs, so it followed logically that I should used the collapse of my relationship for the same reason. It was a more powerful excuse, after all. The way things ended, nobody could blame me.
I didn't blame her. I blamed me. I wanted to talk to her, but she stopped responding to my emails. She said she found someone new. Said she wanted me to send all her stuff to her via international post. Said she wanted a divorce. I guess maybe I stopped responding. I sent some of her stuff. I was barely functioning. After she left, I turned 30 years old and I had nothing so I finally let go of my fear and I dove headfirst into drugs.
Then I got this horrible note in the mail from her lawyers, months later. I don't remember a lot from that time in my life, but I remember this note. It was just before I went into rehab. They wanted me to sign it and send it back to them. It basically said that I was abusive and the end of the marriage was my fault.
She'd said this to me, via email. The court system where she lives is super conservative and religious and they need one of the parties to take blame.
Well, fuck me if I'm going to sign anything like that.
I have no hard feelings. We both did and said things we regret. I got a nostalgic message from her the other day about a Mr. Bungle album we used to listen to when we had mushrooms. It's nice to reconnect, but I don't feel any romantic feelings anymore. I love her, but she's from a very different part of my life.
...
Sad to say, I'm having some problems in my current relationship. I'm not very "good" at relationships in the sense that I approach them more like an autistic person than someone who has read a textbook. I don't like lying. I don't tell women what they want to hear.
If we ever break up, for whatever reason, I will always remain her friend and I will always love her. If she cheated on me, I would forgive her immediately. There is no point doing otherwise. You can't force someone to be with you. Either both parties want to be together, or they don't.
TL;DR
I don't stop loving people because they stop loving me.