Tip's Please?

Me & My baby[boyfriend] are doing very good right now, But im really scard to let go of the past my ex boyfriend,cause i know what me & my ex had was real,& we never officially ended it my mom did cause he was 4 years older then me at the time i was 13 he was 17 & last year he ped away & i miss him so much & i dont know what to do cause im afraid that if i start this relationship with my baby right now & it goes good then what about my heart[my ex] im just so torn & lost ugh i never have loved somebody so much befor & i miss my ex like crazy & my boyfriend i'am datin right now is so perfect for me but im just scard to let it get serious cause i dont wnat my ex to be mad sad or anythin like that even tho he ain here but still i just dont want to EVER let go of my ex,the relationship iam in now is the first relationship i have had in 3 years because iam to afraid to let go of my past please give me your best advice.