Help me i need some advice?

Me and my best friend used to date and my daughter who is not biologically his calls him daddy and he calls her his daughter and we are so close we tell eachother everything. Well we havent been together now for like 2 yrs well i got pregnant at the end of 07 and he was mad because we always said we would get back together once he was done wit school and had his stuff together well i have been in a relationship wit this man that lives wit me for almost a yr and i havent told my best friend because i dont want to hurt him. As far as he knows me and this guy are just friends and he just lives wit me im afraid of what this might do. He wants to come visit this upcoming weekend and i dont know what to do i want to see him but i dont kno how things will go or should i tell him please help