My shoulder to cry on kissed me?

Most likely, this guy has liked you for a very long time, and it sounds like he's put in the effort to show you that he likes you. So, don't blow him off, but don't forget about your ex's thoughts either. So, go out with the shoulder, but make sure he understands that you don't want to shove it in your ex's face either. Get over your ex though. There's a reason why he's your ex, move on/ get on with your life, and give the shoulder a chance, but don't let your ex see it.