Worried about partners drinking

When I stopped drinking my partner said she didn’t want it to change our relationship, but now I’ve stopped I’m noticing just how much she drinks. The problem is that I can see the effect it’s having on her mental health, anxiety and not sleeping but know how defensive she’d be if I tried to reflect that back to her.

It is affecting our relationship either way I guess because she’s not happy and says she’s fed up and genuinely only seems happy when she has a drink. She likes to say that she looks after the children most of the time but the way I see it is that she takes the kids to see her friends who drink and they spend the whole time getting drunk.

I find myself just getting annoyed with how much she is drinking and that she doesn’t see that as being the reason why and thinks that I’m the reason she’s fed up, I know its her thoughts but the last time I said that it went down like a lead ballon which is why I’m avoiding just having an open honest conversation with her I guess.

I want to have a conversation with her about what I’m thinking, but get caught up in thinking that she is her own person and gets to do what she wants, but when I think her drinking is what is causing the underlying issue in our relationship I feel helpless.