a very long post about my son, addiction and regret. I'm so heart broken

Today is a really hard day for me. Today my son turns 9 years. He is the most beautiful energetic happy boy. I love him so much. However I havnt seen him in 7 years. I suffered from drug addiction in my teens and my son was apprehended. It was for the best and he had an amazing life with a family that really loves him, I had another son before him when I was 14 and my mom took care of him but my mom couldn't care for this one. I was clean my whole pregnancy for my son and had him for the first 10 months. It was pure bliss. The father of my son was not a nice person. I was 18 and he was addicted to opiates and sometimes crack. Eventually things got bad in our relationship and he was making me do drugs and prostitute ! I felt so helpless: I called CAS on myself because I knew this wasn't the life for him. He was always cared for, always had baths, always had good and milk and never went without. But the environment was Terrible. My boyfriend and I were always fighting and he threw a phone book at my head and almost hit the baby. I was terrified of this man an he always said if I left he would find me and kill me and I believed him. Anyways after I called CAS on myself they came and evaluated and I told them to drug test us without m boyfriend hearing so they would know what was going on. My son was apprehended the following day, i was allowed visits which I was doing but once he was gone the drug use got more intense it was an all day all night live or die kind of life. My mom and my other son never stopped visits. My ex kept me in a basement with the door locked and it was a scary time. I was kept from my mom and my other son for 4 years. I finally went to jail in 2011 and got out in 2012. My ex left me a while before I went to jail for another person. And shortly before I went to jail I met my now husband. It out and he got a hold of me. We had a very stron connection from the very beginning. When I got out of jail he was in rehab and getting better. I got pregnant with our daughter the first month I got out of jail. It was the scariest thing because I didn't think I was worthy of being anyone's mom. He helped me threw a lot. My life had changed. I was clean and gaining healthy weight an starting to really feel like myself again. I was having regular weekend visits with my son that my mom had but unfortunately I had lost all rights and visiting rights to my son that was apprehended. I had my daughter nine months later. I also got full custody of my son that my mom had the following year.  I married the man of my dreams in 2014 and here we are 11 weeks pregnant with our second. So now we have a house, good jobs. (I'm now a drug and alcohol counsellor) I finished college and we have full custody of my son and our daughter. Life is perfect. Except the fact that I'm missing a really big piece of my heart. I cry every year. Now the family thT has adopted him is amazing. I've never spoken to them but my mom is in touch an my mom, my son and my daughter have visits with them and my other son 3-4 times a year. I feel so lost when these visits come because I just et worried that I'll never see him again but I know as long as he's in touch with his brother and sister there will be a chance. I just hope he knows that I put him up for adoption because I love him so much and wanted him to be safe. But I can't help feeling guilty at times for be able to have take care of my son and daughter and not him. Why couldn't I have changed earlier or have been brave enough to take my son and leave! I'm heartbroken. I just love him so much. This year things have been a little different. I  now allowed to send him birthday cards and present for Easter, his birthday, Christmas, and any other event things like that and I get pictures and little things that he makes for me. He knows I'm his birth mom but we have not spoke or seen eachother in 7 years now. Anyways happy birthday Jonathan mommy loves you so so much an I hope we will be together one day. 
Thanks to very one who had taken the time to read this LOOONG post but I don't talk to anyone about this and I'm happy for this group and be able to share anonymously and hopefully with no judgement and hopefully woth words of advice and encouragement 
Thank you