Sorry - such a simple word yet so difficult.....

Sorry can be such a hard word.  Why is it that it is so hard for me to say sorry to my husband for something genuine but easy peasy for me to say it to a total stranger when I didn't do anything but simply exist?  I am having hard time with this simple word - sorry.  I know it all goes back to my low self esteem and not thinking I am good enough, but I am really trying hard to change that.  I find myself saying sorry to everyone for the littlest things.  You don't feel well today...sorry.  Like it's my fault you caught a cold!  I am typing and my keyboard is too loud....sorry.  I can't control my keyboard people!!  I am good enough dang it.  I am going to learn when it is appropriate - when I freak out when I can't find my keys and accuse my husband of taking them but they are in my purse and when it's not - the kids across the street write all over my driveway (without asking) with sidewalk chalk and I have to drive over their picture to park.