Kleo why not

Kate and Leo ate still best friends but Kate is married to ned and Leo has just released that Kate is his one true love.

Finding Love - A Kate & Leo Fanfiction

Three cheaters, three divorces. Kate is an emotional wreck after her third marriage didn't work out. But her best friend Leo is there for her to help her get through the hardest time of her life. And he's secretly hoping she would finally love him back...

No Line - A Kate x Leo Oneshot

One day, he swore himself that, if he won an Oscar, he would confess his feelings to his one true love. And yet she is in front of him, and he won’t break his promise.