Confused about break up/break? Advice greatly appreciated

My boyfriend and I have been separated for almost 3 weeks. He has had substance abuse issues in the past, I stuck by him through an opiate relapse (I am not an addict). For the past year he's had a second OUI court trial lingering from when he was using. It put a lot of stress on him and also me. I was the only one in court with him that day providing support. Four days later after the court trial where he WAS charged with a second OUI (loss of license, probation, etc), we got into a spat and he completely ignored me for a week, and we were living together. I had to go to him, after he had had guy friends over (lots of drinking) where he told me he wants to move on "and we'll talk about it later". Wanting to do a power move, I packed some things and my dog (we share two dogs, he purchased one and I purchased the other) and went to my parents. It's been almost 3 wks. I hear from other people that he is constantly flip flopping ie: "this is just a break" to "I don't ever want this conversation to happen" to "maybe it will all just snap back into place with us" to "I know I have to talk to her eventually". I wrote him a letter and left it at our house earlier this week and have not heard from him. I kept the letter lighthearted, touching upon the reasons why I do love him and hope that we talk soon. We were together for 4 years, lived together for 2, shared 2 dogs who had a litter themselves and we raised their puppies. 95% of my things are still at our place and he has not called to tell me to get it. We had a very intense love. After every bicker we would always come back in love. It's a connection neither one of us could deny. He made me feel like I could be myself. He made a typical Tuesday night not boring. I could feel his love for me. He has to now quit drinking, by law, which I hear from sources he is freaking out about. I am going to be 29 soon, he is 30. Two months ago he told me he wanted to propose to me within the next 2 years and also told my parents. And here we are two months later. I miss him terribly, it's actually painful, and time is not helping, albeit it has been only about 3 wks since I left. It also doesn't help that our (my) dog is sick and does not have the best prognosis. This is new as of last week, and I did keep him in the loop as per request by him when she was in the hospital last weekend. If he was done, wouldn't he call me to tell me to get my things? We have such a strong friend group too, all of whom are telling him he just made the biggest mistake. Thoughts? I know this is irrelevant but he is always one of the first people to watch my snap chat stories (I know, lame, but had to throw that out there).

How long has he been using? When did he stop? How long and much does he drink?

Does he have a job?

How long will he be in prison? How many times has he been arrested? How many times in prison?

Don't waste another several years of your life with this loser. Stay with your parents. You have to arrange to collect your things, it's your responsibility. If you don't get them in a timely fashion he can trash them, sell them for drug money or money to pay for his very long list of legal problems.

Enlist the help of your friends and family (who are not drug addicts or alcoholics) and get your stuff out of there so you can embark on a decent healthy future and extricate yourself form this nightmare. Do you work? Why are you with someone like this? Don't kid yourself. He is not going to stop drinking or using.

Sadly you throwing your life away like this will make it impossible to have a happy home, marriage, kids, family, future, etc. because now you are getting older and wasted so much time on this irresponsible addicted creep. Hopefully he never killed anyone when he repeatedly put his drug addiction above the lives of others (including yours).

He has had substance abuse issues in the past, I stuck by him through an opiate relapse

For the past year he's had a second OUI court trial lingering from when he was using.

he WAS charged with a second OUI (loss of license, probation, etc)

I packed some things and went to my parents.

We were together for 4 years, lived together for 2

95% of my things are still at our place

He has to now quit drinking, by law, which I hear from sources he is freaking out about.

I am going to be 29 soon, he is 30. Two months ago he told me he wanted to propose to me

I'm having the hardest time trying to understand WHY you would even contemplate marrying a guy with such a background/history?? Do you have such a low self-esteem that you believe you can't do any better that him? I'm really intrigued why you even stay with this guy in the first place.

What do your parents think about you marrying an addict with legal issues?

OP, this relationship will never work until he is healthy, clean, sober and clear of legal problems - for a long time. He is currently in no shape to offer you the type of relationship you seek.

You being lighthearted in a letter or him watching your snapchat stories is irrelevant in the face of such serious problems.

I think it's best you start planning to move forward without him.