Alcohol Addiction ruining us

Ever since my partner started the night shift, he started drinking every night (maybe to cope with tiredness). However, it's slowly becoming an addiction. He's not being his normal self and it's ruining our relationship. What do I do with this? Do I bring him to a counselor as soon as possible? Or do I have to talk to him first? Thank you!

Usually alcoholism treatment is most successful when the alcoholic themselves makes the decision to seek help. It rarely works when the alcoholic is entering treatment to please another person, or to save a job, or to get a drivers license back, or to stay out of jail.
This does not mean that supporting the alcoholic in their decision isn't important. It helps them to see and hear the consequences and pain that their alcohol consumption is causing.
The addiction to alcohol is a disease. Left unchecked, it will get progressively worse. Abstinence is the only real way to recover.
I tried cutting down, but was unsuccessful. It was all or nothing with me. It became unpredictable and I would binge drink whenever and where-ever I could.
Broken sleep patterns can stress people out. I did night shift for awhile and it was too easy for me to drink into the morning. Can he, or will he go back to working days?
Best of luck to both of you.

Thank you Wally58 for your advice. How can I make him realize that he has a drinking problem already since you said that he's the one who should admit he needs help?

Hopefully he is already aware that the drinking is taking over. It would be best if he can decide that it is and that he needs to do something about it.
You can support him and encourage him to seek help, but that may sound like 'nagging' or 'criticism' unless he is really ready to hear and do something about it.
For yourself, you may want to try and attend an Al-Anon meeting to find out what you have to do for yourself (not what you can do about him). You are also in need of support and encouragement as you go through this and you don't have to do this alone.
Best of luck to both of you.

I am already looking into rehabilitation counseling. I agree with you that we both need that. I just have to find the right timing to bring it up to him without offending him or even trigger him to be in denial. Hopefully all goes well with our relationship and his addiction.