How do you forget someone completely and move on with a clean slate ?

I met this person (hereafter referred to as “Person A”) on an online chat platform. As with any anonymous chat platform, we started chatting normally, and at the end of the day, neither of us felt like ending the chat so we left it on until the next day. The next day we chatting talking, and this went on for a couple of days, before Person A on their own accord gave their number via the platform and asked if I wanted to continue talking.

We then started messaging each other privately, and this progressively extended into phone calls, the first of which Person A initiated. We started talking quite frequently, every day, until it reached a point where it became a daily ritual for Person A to call me every morning and wish each other the best for the day and so on. We eventually even progressed to a point where Person A would suggest we video call and talk to each other while we were on the way to school/work

A few weeks into this routine, Person A said that they started feeling something special when they were talking to me, and so did I, so then the confessions began. We started calling each other every day, and our conversations started becoming intimate, where we talked about our life, what bothers us, our life goals and such very personal things. Person A would even complement what they liked about me and what, in their own words “pulled (them) closer” to me. We became each other’s home, where we would return at times of distress to just have someone to “be there” for each other.

After about a month of this, one day, Person A suddenly said that they felt that things were moving too fast between us, and that they were getting too close too fast with me. They then recounted how they were actually in a long term relationship which just broke off a few months before we met online, and so there was reason to suspect that what was transpiring between us was not true feelings but just a rebound effect. This person then said that we step down the status from “relationship” to “dating”. Thereafter, this person stopped all regular texts, calls and video calls, and our conversations became sparse. However, we still texted now and then. I started to miss the usual conversations and the company so I expressed that feeling. In response to that, this person said that they feel like I am too fixated on things between us and so the person’s solution to that is to completely block me off from their life. This entailed completely cutting off access; blocking on telegram, whatsapp and even normal text and call.

It has been almost a year since this happened, and while I have moved on from the initial stage of grief where I couldn’t eat or sleep, this has become a trigger that has been buried deep inside me; just that I have learnt to not let it affect other aspects of my life now. But the things which symbolise my conversations with this person still continue to trigger a feeling, just that I have learnt now how to cope with these thoughts and emotions.

Can I really move on from this relationship and from this person? I feel like this person is the reason I discovered what a relationship actually means, and my definition of a relationship seems to exist on the premise of this person being within that definition. While I do want to move on, I feel like even considering someone else as a romantic partner amounts to some sort of cheating? But I know that this person will never come back again, so I am stuck between having no choice but to forget her and really forgetting her by choice so that I can truly move on

How can I resolve this for myself?