I dont know what to do

You don't mention if they have children, Susie. And does your daughter have good enough relations with her partner's parents to include them in the discussion? The addiction may well be in the family so perhaps his mother has some experience of dealing with it. If not, she will know her son and can perhaps help him to wake up to the situation.

Your daughter is confiding in you so I think she knows it's a real problem and not just social drinking. Can I suggest she contacts AlAnon who give support and have meetings for the relatives & close friends of alcoholics. The people have been through it themselves and will understand your daughter's predicament. I hope it works out for her - and she is fortunate to have you as a supportive Mum.
Best wishes

A friends daughter is in this situation, husband drinks to excess, even first thing in the morning, hides bottles round the house yet argues he doesn't have a drink problem. He won't seek help. The daughter is very loyal and stands by him but it is creating havoc . My friend is increasingly desperate as her three small grandcchildren are going to be affected, if not now then very soon.

I would tell her that her boyfriend is an alcoholic, so she has to decide what her boundaries are. Is she willing to continue to stay in a relationship with him if things don't change? If not, is she willing to demand he get treatment? If he says no, is she willing to leave?

She needs to make this decision for herself. There are lots of books on being in a relationship with an alcoholic that may help her understand the gravity of the situation.

Ilovecheese is right until he admits there is a problem then you can only support your daughter.
I think she needs to be quite firm when telling him of her concerns and perhaps ensuring there are consequences to his actions. I think I would be cutting down on the chauffering and not buying alcohol for home consumption.

She might want to contact the organisation that helps the family of alcoholics. But as another poster has said, he will not seek help unless he acknowledges he has a problem, and the only one who can solve the problem is him. Your daughter can't solve it. Be her support and a listening ear, don't critisise him but always be on her side.

You have a difficult line to tread and I do not envy you - whenever an offspring has relationship problems, trying not to be seen to be taking sides or having undue influence is very hard indeed. I know that all you want to do is put things right for your DD.

I agree that a phone call to one of the drink organisations might be useful for her to do. They might be able to give some perspective on whether her worries that he might be alcoholic are well-founded. But even if he does not fall into that category his lifestyle is having a detrimental effect on their life together, so the problem still needs addressing.

I do think that all you can do is be by her side when she needs a listening ear - very hard for you.

My alcoholic ex still doesn't think he has a problem. He would describe himself as someone who liked a drink or a social drinker. He called me miserable/boring and a host of less polite words because I didn't drink.

Until he accepts he has a problem no one can help him.

SunnySusie, from what you say it does sound as though he's addicted to the drinking habit. Maybe not to alcholic level yet but he's on the slope and denying it. I personally don't have any experience with what you're dealing with but I work with women who have similiar issues.
I'd get your daughter to discreetly contact AA and get some help and advice for herself for starters.
At some point she will have to confront her partner and then if his drinking is out of control, he's going to have to make a choice. All you can do is be on the sidelines with support. I wouldn't talk to the partner myself, you need to stay a step back. But certainly be there for your daughter. It seems to be very common so you're not alone.

He isn't listening to her is he? He sounds like he's totally in denial that he has a drink problem and to me it sounds like he does. Your daughter has worked that out for herself and she is right to be concerned, I'm sorry but I think the longer she lets it carry on with him not addressing the fact he has a problem the harder its going to get. Maybe he needs a bit of a wake up call, not sure apart from ultimatums how she can go about this but she needs to think carefully whether she wants to stick around if he will not get help or change his behaviour.
I stayed in a marriage 10yrs longer than I should of, my husband was by then a full blown alcoholic and eventually died an early death. All you say about his behaviour I recognise.

I'm sorry if you think I'm OTT but the situation is making your daughter unhappy and needs addressing.