The process you need to follow to establish good relationships again after an addiction rehab is not so easy but is not impossible at all. You have to be confident, respectful, beware of getting addicted again, and try to get close to the person you want to get close.

Ways of establishing good relationship after an addiction recovery:

You have to regain self-respect. You’ll lose much after you get addicted, but you have to regain that completely.
Be aware of drugs. You have to keep away from that and never look on them.

Promise your spouse or the relatives or parents or siblings that you will not ever take drugs. Try not to break the promise.
Be honest with them and regain the new self-identity of a good person.

Try to regain their trust on you.
Make new friends and don’t hang out with the older friends or relatives who are on drugs.
Try to get a job or recover the previous one you had before the rehab. Earn money and contribute to the family.
Make them believe that you are completely over the drugs.

Communicate frequently with them and pass more time. It’ll make them believe that you can stay away from drugs.
Participate in outdoor activities or classes, or group meetings of the clubs.