Answer:
Sit him down and talk to him about why he feels the need to lie to you.
A husband who loves you will admit that he has a problem and share his deepest darkest secrets with you. He will vow to work on becoming a better person. Keep in mind that a problem does not go away in hours or days. It might take months, but being in a marriage, you take your partner for better or for worse. Be patient and respond to positive changes. Encourage and support.
But unless he can offer some explanation and involve you in the situation, it may be best for you to part ways.