Let me try. Are you saying that your husband has a drinking problem? Are you saying that his drinking comes between you and your relationship with him? Hmmm.
I think that boundaries are a tough thing, but can you make boundaries in a loving way? Maybe you don't have to say that you understand, if you don't. If he blew you off if you already had plans because of his drinking, I think telling him firmly, directly, and deliberately the next time he called (don't call him) that you appreciate that he is calling now, but you prefer and expect a call from him in advance. This would be out of respect to you or anybody if he were to break a date. (And that would be all I would say.)
Re: His coming over and sweet talking you. I think it is great that he pursues you. My H, 'A', hardly looks for me. But back to you...You kinda' have him in the palm of your hands. He is probably looking for you to ease his guilty conscience, and he probably knows that you will comfort him and make him feel better. I don't think you are being used. I think he just wants to not feel bad because he wanted to drink and he knew he blew you off. He knows it isn't a nice thing to do.
I guess, as difficult as it would be, if he wants to come over, tell him you have plans. Make something up or actually make plans with a friend. I wish my H would at least give me the opportunity where I could at least feel like I was being pursued and play a little hard to get. Go out to dinner or a movie with friends. Go rent a movie and invite a friend over. The art stuff sounds really cool.
Also, don't blow up. I'd like to, also. In the long run, it wouldn't be a good thing. If he does have a drinking problem, go to Alanon. Don't be an enabler by easing his guilty conscience. When it comes to blewing off people, dates, work, it's a problem. However, it also is a sickness, that is, if he does have a drinking problem. That doesn't mean he doesn't love you, it just means that he has a sickness that is treatable if he wants to be treated.
I know that you want to feel loved, and I am sure that he loves you and doesn't want to lose you because, like I said, he knows he isn't making the right choices. I would suggest not to tell him what he wants to hear that... 'it is ok'...because it isn't. But I think you know that.
I think it will be baby steps but you have to hold tight, too. Act as if you are strong, even if you cry at night and write here. Be nice, but firm. Act as if you are busy doing other things. At first, he might be mad because you didn't make him feel better, but let him FEEL guilty. Maybe he needs to feel a little fearful that his problem is not yours anymore and that you have your life...even though you are hoping inside that he will find a the will to straighten out.
