This buddhist philosophy that I've been using to try and make sense of my life comes down to a pretty simple premise I think. It is this:
Everyone wants to be happy. Happiness is absence of suffering.

This is where it starts to get a bit more complicated though when one contemplates what suffering is. Buddhists would tell us that all of our troubles are within us. Any external vexations are only as the result of "attachments" (sorry for the jargon). Attachment is, if I've understood correctly, the love or desire for a person or thing with conditions. In the case of people, it would for example be the love of someone on the basis that they will love you back and give you what you need. For objects, an example would be the delusion that a bigger house, a nice holiday, more money will make our lives complete.

All of this is well and good, but applying it in real life is the challenge. I'm failing badly at the moment, attached as I am to someone and overinvesting in the perceived happiness they could bring me.The relationship is on hold right now. Once emotion is involved, all of the philosophising in the world won't ease the longing. Maybe time will do it - I'm banking on it if I'm honest.