I don't think a husband or wife should have to ask their spouse where they are going because it should be mature respect. When I'm going out to visit a girlfriend or go shopping in the evening and my husband isn't home I leave him a note and let him know where I am and vice-versa. If I'm not gone for long I don't generally say anything. If I'm out with my friends and plans are changed and I'll be late if my husband is still up I let him know. It's not so much about someone knowing your every move, but also for safeties sake. However, if your girlfriend or wife comes home they sure don't need the third degree for their every move. It sounds like you think she could be cheating. You have to start communicating.