help out a sister...

salaam to all,
I just came across this ***site while googl-ing some islamic forum.
I am a member of a few other forums and have a problem at the moment but I cant discuss it there as it will give away my identity.
I am a muslim woman,living in North America,married for 6 years now and do not have any kids.
I love my husband to bits and although he is never vocal about it but I know he loves me too.
A few days ago something happened.He went out on a weekend night and told me he is going to a friend's house whom I know well.
he returned home at 4 am and was drunk!he stank of something weird which I assume was beer or something ,was fumbling with his keys while opening the door etc but wasn't totally passed out.
2 days later I found some girls' number on his cell phone.I called that number using his phone and she picked up and said his name "hi *****" meaning that she knew him
when I asked him he said after lots of lies that she was a show girl he met that day while he was at an adult bar. and assured that nothing more happened.although I still have a hard time believing that how come they exchanged phone numbers then.but maybe I am in denial and dont want to think down that road .
today I found out that he spent $700 that day.I asked him he says he paid for himself and the other people who went with him.
Although my trust has been shattered and it still hurts a lot and I just dont know what is true and what is a lie.
My initial reaction was to leave him and go back to my country but that is not possible so that did not happen and neither do I want it to.
Recitation of Surah Yasseen has helped me in these few days to find a bit of calmness within me but I dont know what to do.
In the 6 years we have been married there has not been anything suspicious on his part.
I want to forgive him and a part of me already has.
I want to forget it or atleast find some solace.
I want to know any kalam e paak I can read to make my marriage stronger and safe from the sha'itaan and something I can read and pray that Allah swt guide him to the right path.
He does not pray himself...just an occasional prayer here and there and I have kinda given up on it now.
He does say it was a mistake and will not happen again.

I am sorry for such a long post.and am not sure where to exactly post it.I will really appreciate any sincere replies.
Whatever he did is between his God and himself and although it shattered my trust I need to find peace for myself.

Thanks.