Grieving over past loved ones

Today they took my first love off life support. I can't help but feel a deep sorrow. He was only 30, never made it to having the family he dreamed of. He was my first, he was my childhood friend, his family was like my family. We had a talk last year about how we would probably always be in love with each other even though we knew that chapter in our life had closed. I feel so lonely in my grief. I'm scared to talk to loved ones about how I feel because they might not understand. My SO now is my world, he is my rock, I would never hurt him. I just feel like s chunk of the girl who I was is missing now. Is it wrong to mourn over the death of someone you had a past relationship with?