I read your post and thought that’s my life. Difference is im 6/7 years into the relationship with kids. Like you describe, it’s like living with two people, the ‘overly nice one’ you want all the time and the ‘nothing matters but what I want’ version which puts you last. It will only change when he wants it to and he doesn’t sound ready. Five months in, you should really think is this what I want long term as he could decide to get clean tomorrow, or you could be living this exact same life 6/7/8 years down the line and would you want that? Good luck x