scared
Take him at his word re the marriage; do not let him backtrack and do not backtrack yourself now. You and your children have been through more than enough crap already because of his alcoholism.
This is probably not the first time you've questionned his drinking either.
Its not just you who has been profoundly affected by his alcoholism; its your children as well. This is not a good environment for you, let alone them to grow up in.
You need to remember the 3cs when it comes to alcoholism:-
You did not cause this
You cannot cure this
You cannot control this
You do not need such an emotionally bullying alcoholic in your life; he is also like this because he can be like it. You do not have to be his crutch, enabler or emotional punchbag any more.
What are you both teaching your children about relationships here?.
He has and continues to choose alcohol over you; his primary relationship has been with alcohol for many years now. Like many alcoholics as well he is selfish and in complete denial of the problem. He likely has built up a strong tolerance to it over the years so does not appear drunk but he is and excessive drinking like he is doing is killing him regardless.
Apart from seeking legal advice to end this loveless marriage you need to talk to Al-anon as well; this is their office address for Eire:-
Republic of Ireland:
Al-Anon Information Centre, Room 5, 5 Capel Street, Dublin 1, Republic of Ireland
Tel: 01 873 2699 (Helpline 10.30am - 2.30pm, Mon - Fri)
Alcoholism is a family disease; you and your children need ongoing help and support after you separate as such men take years to recover from.