I need some insight

Okay so long story short.. I am in a relationship and have been for 2 years with the love of my life. I have a 3 year old son that's not his but he has taken up that daddy role no question asked. so my current situation is... hes a drug addict.. so next thing. he is finally convinced that going to rehab is the best option at this point... now... we live with his grandmother as I have no family. my relationship with his family is wonderful. so we are getting a bed booked and he's going for 30 days. so ... There's that. now... this is going to sound selfish and a tad bit immature and I'm planning on going to meetings that are meant for the families of a addict but I feel like that I am losing him and I am so scared that he isn't going to love us the same once he's sober.... I need reassurance and to basically get this k ff my chest because I want nothing more than for him to get clean. but I am so scared to lose him at the same time. I habe fought so hard and so long for this. I just want him happy.... tell me I'm not crazy please