One that I have to assume points out some sort of deficiency in me, otherwise I wouldn't be having to repeat this lesson.
Jimbo, there is no deficiency in you. You are a great guy who has been dealt the wrong cards twice. Don't let these experiences take away from the great future you have in front of you.
So what if you have been down this path before, it doesn't mean there is something wrong with you. Whether being married or dating, we go through these things. If I looked at my dating record I would surely think I was destined to a long life of being alone. My track record was not great. You put these things to the side (once you have had time to heal) and you move on.
Grieve for your marriage but don't blame yourself. You are the victim here but you will survive this.