-See Yourself again in Your Own Life
-Choose another better version of that lover
-Choose another version of that lover
-Choose a more fun lover than that other loer
-Choose the opposite of that other lover
-Trust that there are more lovers (because there really are multiple lovers that exist for one person, and there are multiple soulmates)
-Have less high demands and expectations for yourself and your relationships overall, less expectations less stress
-Find a nice hobby to spend time with and change your focus
-Write about it (journaling) or talk about it with someone you trust (maybe even a counsellor or someone outside your network)
-You don't especially immediately have to trust someone, it is actually your own feeling and your own story line, it is not mandatory, you can talk about it if you want but be prepared that not everyone might take you seriously and lots of people generally don't know how to deal with it when someone comes with this kind of problem. Even Professional Help might not always be adequate, because they usually steer towards "so you didn't do any suicide attempt yet? and you don't have a plan either?", as if it works that way, the reality is way more subtle, and it goes from mild to sever depression, then psychosis or tiredness and restlessness, and IF you are lucky some manic episodes.
If you choose another lover, does that mean you gave hope up and you don't love the other person? NO, but you cannot be haunted and hunted to death because you love someone and think at the same time to jump in front of the train because of unanswered or unreciprocated love. Finding someone else suitable, better, similar, opposite or alternative is a coping mechanism, not always ideal, but it definitely works to postpone your own death and WHO KNOWS, maybe you will find that Special Someone in Another Person, but the first step is to BELIEVE it is actually possible!