I've been on both sides of this with the same person. Really stupid decision making following (and, in case anyone actually reads and responds, I'm fully aware that this is not a story that makes me look like a good person, and I made a lot of shitty and selfish decisions that took a toll on both myself and my ex and years later I still feel bad thinking about it):

Essentially, I went out without her, cheated on her, went to her place to fess up and break up with her. Shortly after tried to talk my way out of it. She was unreceptive at first, but slowly let me back into her life, though constantly telling me she'd never date me again. We got to the point where we were essentially dating, but she wouldn't use the word. I kept asking her to just let me take her on a date and to give it a shot. This went on, literally, for years. I was hopelessly addicted to the singular goal of being with her. I was so convinced it was what I wanted. Finally, I decided to ask one more time, and if she said no that was it. I brought flowers to her door, told her how much I cared about her, and promised I'd never ask her again if she said no, but that I wanted to take her on a date. She looked truly upset to say no, but she did, and I left.

As promised, I never asked her out again, but about a month or two later we were hanging out with mutual friends and eventually she tells me she's interested in dating me again. Mind you, as this point I'm finally feeling like myself again - not caught up on the prospect of being with her and understanding that we just couldn't have a solid relationship. I told her how I felt, and basically the opposite from above ended up happening where she was longing for me for months and months and we'd make out and sleep together, but I was unwilling to commit to a relationship.

Finally, it just... ended. I don't even remember how, exactly. But it freed me from the most toxic and emotionally exhausting relationship of my life. I was severely depressed for most of it, and it was honestly just one of the worst experiences of my life. It's just not worth it.