I'm going to second velma and PW when they talk about how eventually, when you know someone lies about EVERYTHING, you simply stop asking. And then you stop talking, at least not about anything beyond the weather and similar topics. And at some point, you realize there is nothing left.
You posted the following:
I’m torn in between, because when he’s not drinking, he is just nice and mellow guy. He is the type of functioning alcoholic.
You've mentioned two important points here. One, that he's a nice guy when he's not drinking. I think everyone who comes here has said that, somewhere in their early posts. I know I certainly did! But what I was told, and will pass on to you here, is that "the nice guy" and "the dishonest/irresponsible/cruel/whatever other bad behavior drunk" are one and the same person. They cannot be separated. One comes along with the other, like horrible Siamese twins.
The other point is the "functioning alcoholic" reference. What most here will tell you is that "functioning" is not a type of alcoholic, but a stage. They ALL "function"--until they don't. And it's not like you get an email 2 weeks in advance of the DUI or the car crash or the loss of a job or whatever other catastrophe marks the end of the "functioning" stage, so that you know you need to get out now; you'll still be there and will get to share in the mounting debts, legal costs, loss of your home, and so on.
Some time ago, an SR member posted about "functioning alcoholics." It was tremendously helpful to me in clarifying my situation, and I saved it to refer to as I moved forward. I'll re-post it here, hoping you'll find some help in it also.
I'm not going to be very eloquent here, but when people who aren't in it use the phrase "functioning alcoholic" or imply that the situation isn't that difficult because the alcoholic is able to maintain a job and doesn't beat anyone, or because they "obviously" care for their families, those people are dismissing the biggest parts of what makes humans who we are. The fact that a person can hold a job, can move about the world without stumbling and hurting themselves or others, that they can make a sandwich for their kids - those functions don't make a human a full and complete human. A robot can do all of those things. To truly function, a human has to be able to do more than that, and honestly a human doesn't need to be able to do the things above to be able to "function" as a human being. The other things - like connecting to others with truth - are so much more important. I've come to the realization that there's no such thing as a functioning alcoholic. There may be physically capable alcoholics, but that's as far as I can go.
"Connecting to others with truth"--is that happening w/your "functioning" alcoholic?