Snape had undoubtedly loved lily evans. But something many didn't know is that she loved him back at some point in time.

But by then, it was far too late for the boy with the only black hair. It was far too late for his old eleven year old self to make and appearance

So, lily potter nee Evans ended up with James potter, and she loved him more then she even loved Severus.

But sometimes, after reading his diary and finding out about the small crush lily had harboured on him- Severus wondered what life would be like of lily potter nee Evans had become lily Snape nee Evans instead.

But it was useless to day dream, right?