He quit drinking

I've posted anonymously before and again I will be reading comments and taking advice but not commenting myself.

So he recently quit drinking, he's done it before and after at least 1 year he relapsed and starting drinking again.

My problem is trusting him. We don't currently live together but will soon. He calls me while walking to the store or wherever and everytime he wants to hang up I think he's doing it to go into a liquor store.

Now let me point out he is NOT a phone person at all. Never was and actually talks to me more on the phone than he ever has with anyone else.

But it's SO HARD!!! I am trying to be there for him and I want to believe him but it's so hard. I don't want him to think I don't believe in him so I'm afraid to question him. I did once or twice and he didn't get mad or anything but I just need some friendly advice on how to get through this.