You have only one life. I think you need to tell him. He will be hurt. He will be crushed. You have to keep the lines of communication open. He may or may not maintain a friendship with you in the future, but you should not live your life as a lie.

You are being unfaithful to your husband. You need to end the affair or end the marriage. It is not fair to your husband to be married to someone who does not want to be with him. Also, there's no sense in you staying in a marriage with someone you don't want to be with. Just be sure you want this other man. Once you end your marriage, that's that.

You should talk to your husband and resolve the matter before you get into another relationship. You have no choice but tell him. The question is why did you break up with your ex-boyfriend, did he dump you?. This is a decision you have to do, since you hav to pay for the consequences. But is not fear for your husband that you are cheating. Because if you ex-boyfriend dumped you,he may dump you, again. Good luck