Most Helpful Girl
Forgive, but do not excuse.
He did something wrong, and you're right - people rarely have a habit of growing stronger morals, but weaker ones over time. I would not continue to date him, but I would call him to say that you:
1) Forgive him
2) Think you both want different things out of life
3) While it was fun while it lasted, you do not see this working out long term
4) I am not mad at you, but only disappointed with the situation
5) Thank you for the apologies. I have accepted them, forgive you, but cannot excuse what you've done by continuing to date you.
Now if it were ME, and it was the very first weekish of dating, I would be very forgiving, because at that point - we would have just been getting to know each other. If he was a fantastic boyfriend to me and I couldn't imagine him doing that now, and he was apologizing because he felt bad for me and not so much for himself, I might consider gettting back with him. I don't usually get very jealous though (maybe because I've never gone through a cheater experience), but I would like to think it wouldn't bother me as much as most people seem to react. However, in your case, you seem to be pretty hurt by all this, and I don't think the relationship would ever be normal again after this kind of blow up. You're both better off starting again with different people.
Forgive = acknowledging wrong and accepting it with grace = granting mercy
Excusing = acting like nothing bad ever happened.
Grant him mercy. He obviously feels terrible, even if it is for selfish reasons. Grant him the mercy of knowing he is forgiven and having closure. Then move on.