How long can you last “in love” with someone?

I want to know about someone else who is going through the same thing as me, it’s not something serious but it hurts on a sentimental level.

To summarise I fell in love with a girl at the beginning of 2022, we never became a formal couple for various reasons, the point is that it’s been a long time since we stopped relating and for a period of time I stopped thinking about her and I thought I had gotten over her but recently I accidentally saw some photos on her social networks and I feel “jealous” that I can be with someone else even though we are no longer related, I often miss her but the strange thing is that when we were together there were too many arguments.

What am I supposed to do to stop thinking about her? At this point I have tried to meet new people but I just don’t feel a bit of what I felt with her and the feeling of needing her is very confusing.

Any advice?