Carry a torch for somebody
Definition 1 of 1
Pro Tip 1/3Unrequited Love
This phrase often suggests feelings that are not mutual, similar to loving someone who does not love you back. 
He's been carrying a torch for his college sweetheart, but she's happily married to someone else.
Pro Tip 2/3Emotional Weight
The phrase evokes a strong sense of longing or deep emotion for another person. 
At the reunion, it was clear he still carried a torch for his first love.
Pro Tip 3/3Not Always Romantic
Though often romantic, it can refer to a platonic ideal or bygone connection. 
She still carries a torch for the friendships she had in her youth.