Talk to him about it. As horrible as it seems to say "I`m not sure how I feel about you anymore," it would be much worst to walk out the door with no warning. Maybe he feels the same way, or maybe the two of you can work it out.
If you want the marriage to work you can always see a marriage counselor. If you have no desire to continue with the marriage you could seek legal advice from an attorney regarding a divorce.
There are several options when one discovers love is lost: continued loveless cohabitation, relationship counseling and therapy, separation, divorce, or murder.
