This is a very difficult question, as I think you may be saying that he loves you as a person, may love being married with you and sharing your life together, but isn't in love with you as a woman,...
Your husband is cheating on you! It's obvious! Another thought: Your husband may or may not be cheating on you, but the line "I love you, but I'm not 'in love' with you," usually means he has one...