Married but still in love with first love

I am married for 15 years with 2 children. I met my first love recently and we still have feelings towards each other. I am his first love too. We know both of us are married but we just can't stop ourselves from loving each other so much. We met secretly without our spouse knowledge and we have been spending nights together. I am confuse.We lose each other before and we are not gonna to lost each other again. Pls help