Here’s a summary of some science of love, from one biological perspective.
Love is a mechanism nature uses to ensure that we reproduce and that our offspring survive. The chemicals involved in our brains can make losing love one of the most painful emotional experiences we can have as human beings. Many people have died from it, in fact. Yes, you can die from a broken heart. Physical pain and the pain of social rejection are experienced in much the same way by your brain.
If your partner’s oxytocin receptors get blocked, they will lose interest in love. On the other side, if you are addicted to someone, you might want to find a way to block your oxytocin receptors.
One way to look at love is to understand that kissing and hugging elevates oxytocin. People who are in love have unusually low levels of the vital neurotransmitter serotonin and people with obsessive compulsive disorder are unusually insensitive to serotonin, so there is a chemical basis for the view that love is an obsession.
During rejection, the breakup becomes a puzzle that must be solved and things can get pretty uncomfortable. Eventually, your brain chemicals will normalize, so just ride it out. While you are going through a break up, it’s okay to cry, but never overwhelm yourself with grief. If you start to go too deep into that, just slap yourself or something and snap out of it. Don’t do it. That’s not going to help you out. Be kind to yourself. Keep busy. Do things you really enjoy and keep up your social network.