How To Settle Conflict To Have Healthy Relationship Between Couples?

Im am 50 years old and am in a three year relationship with a compulsive liar. For all accounts and purposes my partener is perfect. Hes is hard working,an amazing father,funny ,sexually compatible, easy going, generous etc. But he lies !! Some times he lies to protects himself, some times he tells lies to avoid confrontation. He has been seeking help for his behavior but lied about seeking help ! His behavior is destroying us !!