It depends on the characters and their development. Maybe a mutual understanding and acceptance of the end could be a good way.
You could have a bittersweet ending where the couple realizes they have to part for some noble reason. It leaves the readers with a mix of emotions.
It might be a good idea to end it with a heartfelt conversation where they both come to terms with their feelings and decide to part amicably, leaving the reader with a sense of acceptance and closure.
One way could be to have a bittersweet parting where the characters realize they have different paths. Maybe one moves away or has a career change that makes the relationship impossible to continue.
You could have the characters realize they have different life goals and part ways amicably.
One way could be to have a mutual understanding and a peaceful parting. Maybe the characters realize they have different life goals and part on good terms.
Another way is to have a big argument or betrayal that makes the relationship irreparable. However, be careful not to make it too melodramatic. It should feel genuine and based on the characters' personalities and the dynamics of their relationship throughout the story.
You could have the characters part ways amicably, realizing their differences and choosing to move on for their own growth.
One way to end it is to have a big conflict that can't be resolved, showing that love isn't always enough to overcome everything. Or, you could have one of them move away for a job or family reason, forcing the end of the relationship. Just make sure the ending feels real and makes sense within the context of the story.
Ending a love story can be done by having one of the characters fall out of love and find new interests. This could be due to personal development or a change in priorities. Another option is to introduce a third party that causes complications and ultimately breaks the relationship.
One way could be to have a bittersweet parting where both characters understand it's for the best. Maybe they have different life goals or circumstances that force them apart, but they part on good terms with fond memories.