blast from the past: for my ex?

Long story short:dated this guy John who was a good guyfriend and it did not work out so we broke up,We are on non-speaking terms,I tried to be friendly and asked him to coffee but he turned me down. We were enagaged for 13 hours after he turned me down for coffee and the following day realized that it was too fast. Anyways here is what happened: last semester in November I found out that I was 6-7 weeks pregnant and I knew it was his.His uncle passed away so I did not say anything at all.I had no idea what was wrong with my body prior to me finding out that I was pregnant: throwing up,running out of lecture during class and throwing up,the smell of certain foods making me nauseated,eating carbs but not meat.I thought that I had too much meat to eat which if I do then I do not eat meat in large quantities for a while.I thought that stress was causing me to throw up as it has done in the past. Anyways so I had an ultrasound and then a couple of days found out that I had a miscariage.My then bf now ex John never found out about any of these things since he was dealing with his own grief.For 3 weeks my ex,friends and family took care of me-I would barelty call friends back,hit rock bottom,was behind in my classes and had some explaining to do to my teachers on my behaviors such as crying out of the blue or throwing up so much.They found out about my situation(all 3 of them-I am in college).So my ex thought that I broke up with him since I would not answer his calls for 3 weeks yet I was depressed which was normal after the miscariage. My ex bf,the guy that I dated before this guy JOhn, for 4 yrs helped me and paid for doctor's visits,etc. Here is my question: my ex and I are on non speaking terms and he is pretending as though I do not exist in his life even though he has been in love with me since 2008 or so. I was thinking about writing a letter about what happened last semester in order to have closure and give it to him then walk away. The letter explaining everything including why I could not be by his side when his uncle passed away because I was sick and pregnant.

Is this a good idea?I know that he would be in shock though so I would write it by hand then give it to a friend of mine to give it to him.That way he never has to see or hear from me and it would be an easier thing.I do think that he has the right to know on why I was the way I was last semester since he made me to be this non -caring person as one of the reasons for the break up which is not true.I was not there because I could not and had to see doctors and was nauseated and missed more than my share of classes which I bombed in the end.