The short answer is, "yes," you seem to have a very pronounced issue with honesty.

From the things that you've said, it might be possible that you're in a bad relationship and this makes it hard for you to be honest. It also might be that you've been so dishonest, so often, that you've turned it into a bad relationship.

Instead of saying, "I'm going to be gone for 20 minutes," say something like, "I'm going to be gone for a while." If he insists that you give him a very precise estimate, tell him that you can't. If that isn't acceptable then I would say that he has way, way too much control over you, and you are probably in an unhealthy relationship. As an adult you don't need to give a detailed, precise itinerary of your every moment to someone you're in a relationship with. If this is the case for you, something is very off. If you are giving bad estimates of how long you're going to be doing things, try not to give estimates at all. If he insists tell him you can only give a rough estimate because you're not a psychic.

I don't know what else to tell you. Once you damage trust it takes time and effort to rebuild it. If you think that lying about "little stuff," "infrequently" is going to lead to a better situation I think that you are mistaken, but I don't know all the details of your relationship. It sounds like there are a handful of distinct problems.