What would you do if you kept catching your partner in a lie?

Say you've been dating for 2 years now. You talk about marriage, kids and a life together and he has told you he is going to make you a part of his family blah blah. Pretty much your dead set on getting married to this person.

You two made promises to each other to never lie or to hold anything back if it was something we were both uncomfortable with. He swears and promises on his God, your relationship and the life of others that these promises wouldn't be broken and if it was, he would say something and I promised (didn't swear or anything) as well.

You keep catching him in a lie over and over again over the course of 2 years. What would you do. I would use my issue as an example but something important to me may not be important to you so use any of yours experiences if you like. I just want to know if forgiveness is really worth it after so many chances.