Piper and Leo still had to deal with the consequences of their forbidden romance after getting back together. When the Elders issued an ultimatum about Piper and Leo's relationship, Leo proposed to Piper, who, after some hesitation, accepted. They tried to marry in secret, but the Elders were told of their plans after Cole exposed them to the magical community. As a result of this, during the wedding ceremony (with Prue and Phoebe as bridesmaids and Grams as the High Priestess) the Elders painfully orbed Leo away. When the Elders forbade Piper from ever seeing Leo again, Piper decided to go on strike from being a witch. But once she realized that she still had a job to do and she still had to save innocents despite her anger over the Elders' decision to forbid her from being with Leo, the Elders sent Leo back. The Elders said that Piper showed great courage in protecting innocents even when she had the love of her life taken away. The Elders however, allowed Piper and Leo to continue seeing each other on the condition that their relationship would not interfere with their jobs.
Leo and Piper were finally married by the ghost of her grandmother Penny in a special ceremony. The sisters' father Victor, Phoebe's half-demon boyfriend Cole Turner and Detective Darryl Morris attended the wedding, and the Elders sent Patty back to Earth for the day to attend the wedding as a gift. Their marriage has produced three children; Wyatt Matthew Halliwell, Christopher Perry Halliwell and Prudence Melinda Halliwell.
But this was not to be the end of their struggles to have a relationship and have a magical life as well. Leo had to leave Piper and his son for a short time to be an Elder, but worked around it. After Leo had killed an Elder who was trying to capture his son Wyatt Matthew Halliwell, Leo ended up seeing floating green heads and then, unfortunately for him, ended up killing another innocent Elder called Zola.
Leo tried to get over this but was ultimately turned into an Avatar who corrupted the girls to create Utopia but this went wrong. After this is Season 8 (Veya Con Leo's) Piper learns that the Angel of Death was after Leo and so in an attempt to stop Death taking him a spell was cast and every man in the world was turned into Leo. But this back fired and Piper had to call down the Angel Of Destiny who said that she would take Leo and when the Ultimate Battle had been fought Leo would be returned to them. So with the help of a demon Leo was frozen and taken from Piper but he is later returned to her after the final battle.
source wikipedia
