The opening of this article would suggest, plainly, the direction to which the thoughts in it would take: it is about love affairs, not mere friendship that we are dealing with – here.
Relationships do happen, and they (somehow) end up as trash – in some instances. Although, it is always an heart–wrenching experience for the party (one of the partners) who does not want to let go: the other person that is clamouring for breakup (too) got a lot to fight against, emotionally, but he/she just got to let log due to many personal reasons.
Perhaps, we could learn some things from what the Bible, in Song of Solomon chapters: 2:7, 3:5 & 8:4 say, “[He said] I charge you, O you daughters of Jerusalem, by the gazelles or by the hinds of the field [which are free to follow their own instincts] that you not try to stir up or awaken [my] love until it pleases.” Song of Solomon 2:7, AMP.
With the above text, we could say that some people were not, actually, ready for a relationship before they got into it, hence, they had to back out at a period. No matter what, like D’Banj says in one his hit tracks ‘don’t get it twisted the love is a beautiful thing’ – true love is something that should happen to everyone that desires.
You just had to let it go
The bitter truth is that the harder you try to make someone stay (when the person had, already, packed things up between the two of you) the stronger the person becomes and the more degenerated you become: you will become sapped from trying.
Rather, you got to do yourself some favour. Just move on, forget self pity: go for a new love with your mind inclined to (never) allow whatever went wrong in the past relationship to happen in the new one you that you are going into.
The only time that you should do everything to restore a relationship is when you have been married with the person, but he/she is (now) clamouring for a break up – no, you will not want that to happen: so, do not let it happen, at all: may it never happen to you.
Notwithstanding, if the relationship was just at the level of courtship/dating, then let the partner go – if he/she wanted it.
Happiness in a relationship is a product of two, not one person
It is true that (as an individual) you are responsible for your happiness. Yet, we want you to know that being in a relationship with a person (with much or equal degree of love, without deceit) generates much happiness in each of the partners involved in such relationship.
As a result of this, when your partner is breaking up with you – allow him/her to follow the instincts within him/her. With time, you will heal from the wound and lead a better life with another lover.
Notwithstanding, there could be a relationship break up (too) for the good of a partner: imagine being in an abusive relationship? It could be the guy that abuses the gal or vice versa – in such instances, there can never be lasting happiness in the relationship. So, the best thing will be to break up.
Happiness counts so much in intimate relationships, and it will be best to fold things up if it is, only, coming from just one of the partners, instead of the two people.
Look at what Jill Murray got to say to parents, even though it is one-sided, because guys, also, suffer abuses (especially emotional abuses) in relationship:
Verbal and emotional abuse can be the most devastating type of power control. In this setup, the boy systematically degrades her for his own faults, making accusations, humiliating her in public, destroying objects that are special to her, telling her she’s crazy, and using menacing looks and intimidation.
Without doubt, no happiness will last in any abusive relationships (so, it is nice to let such pack up): yet, whether due to abuse or other reason(s), if a partner decided to break up a (dating/courting) relationship, it is always good to let him/her be – so that you can find peace and love further, where it matters most.
 Jill, Murray, Protecting Your Teen Daughter from Controlling, Abusive Dating Relationships, Pg 31.