Cheating husband?

Hi
I'm new to this so will try and keep it as short as possible. I've been with my husband for 28 years married for 25 years and until last year I would have said our relationship was good only the normal life stresses. We have always worked together running our business.

3 years ago my husband started working for a manufacturer that we used. He has an expense account and the job involves a lot of entertaining clients and trips away. I informed my husband from the beginning that it wasn't a jolly up it was work and that he should treat it like that

During December 2014 there was a Christmas party for one of his big clients (no spouses) I noticed a difference in him from then he came home and didn't talk about it. I asked him he said I was being ridiculous! Then in June last year I caught him lying about a meeting that he had. Apparently he had the meeting in the morning then they were going horse racing in the afternoon. I found messages on his phone. There was no meeting I confronted him he said he didn't want to upset me because didn't want it to look like he was out enjoying himself while I was at home running the business etc I said don't do it again.

In July my nephew died suddenly age 28 he was like my son you can imagine the devastation to myself and my family. My husband was a bit distant the day after the funeral he went to work and didn't call me till 19.30!!

The next few months were a bit of a blur in September I was away for a few days when I came home I found out he had been out with these clients again basically he lied about what time he went and what time he got home!! There have been a few other times when he has been so desperate to go out that regardless of the consequences he has gone

He has been drinking a lot and on his last business meeting apparently got so drunk that he past out fell over and can't remember any of it. I made him call his boss in front of me so I could hear the story first hand. I then said he needed to call his client as I was interested in hearing what he had to say my husband refused and then secretly messages his client to say don't answer the call but I caught him doing this. I went mad and he said it was because he takes cocaine sometimes when he is out with them!!

Also I found a blank text on his phone from a women who works at the clients offices. He says he never says 2 words to this person and can't remember getting a blank text then he says it must have been about going down for diner. He text her back twice then a 2am text which he doesn't remember

The only reason I know all this as they were all deleted is that I sent his phone off for forensic data and there were a few other deleted messages to this woman

He swears blind he hasn't cheated and now he is back to being normal!! I don't really know what to think to be honest!! Why would anyone delete innocent messages?