What a roller coaster ride! Two weeks ago he was ring-shopping with you and then he leaves to frolick with a stripper! You won't be well-grounded for long if you stay with this guy. Let someone else change his dirty diapers! If you want to take care of someone so bad, get a puppy!
Suggestion: Read your post and pretend that someone else wrote it - how would you advise them? Then ask yourself why you would even consider giving him another chance - and why you're a bad-boy magnet. You might consider some counseling for yourself - what he's done is dispicable, but you're the one who keeps ignoring the red flags and going back for more!