Anxiety with my boyfriend drinking

In the beginning of our relation my boyfriend was borderline alcoholic. He would drink cases of beer and multiple bottles of wine each week. He blacked out at least once a month for 3 months. I confronted him and he apologized and tried to change. Since then he had 2 more times when he had big drinking nights and got out of hand. Each time we discussed it and talked about what went wrong. In the last 12 months his drinking has gotten much better. He has been buzzed but only drunk 2 times and never like the beginning. (He used to have 10/12 drinks in a single night but rarely goes over 5 on the nights he drinks now, which are more rare.)

While he has gotten much better I still have anxiety when he drinks. He admitted he was in a dark place when we met and has no plans of ever being that way again.

Now he will drink 3-4 x per week maybe 3 - 4 beers in a sitting. I still get nervous. Is that normal? How can I let go of the worry? I know that 4 beers 4 nights a week is not a lot, but I still get nervous. I’ve told him and he says he understands why I’m nervous but doesn’t think there is any issue with his drinking. We are thinking about marriage and this is the only concern I have. Can I get over it?