I am so, so sorry love
If you know my posts, you will be aware I abhor cheating and would advise against staying with someone who can do this to you
however
You have decided to give it another go. Fair play to you
Now in that situation, I would advise that you look at his behaviour now and in the future
you know he must have lied and deceived and made an absolute cunt of himself in the past
that is a given
seeing that in print will not help you now (unless you need an excuse to end it with him...and tbh, you had that already)
so, I would say...let the past go
and make sure the present and the future is taken care of
he must be completely transparent wrt to email, texts, nights out, mobile phone, skype etc etc
nothing must be hidden
he must be home when he says he will be
he must show you every day how much he wants you not just his comfy crash pad until something better turns up
all the best, you sound lovely x