I dated someone for 4 years, but med studies left me no time to keep up. We agreed to be friends with benefits instead, thinking we'd resume things later anyway. However, my feelings slowly drifted and I now like someone else. Though I'm not technically my ex's girlfriend anymore, I know it'd hurt him, especially due to his depression and sensitive nature. What's a kind way of letting him know? Like I don't know how to start the conversation -any ideas or suggestions?