For once, I somewhat agree with Tony
But its important in a relationship to not only be sensitive to the other person, but be patient and not overly sensitive as the other person
You need to learn what can make them upset and avoid saying things. Ive had to learn this and if I know something can make her annoyed or upset then I wont say it. Also making sure your tone is not harsh or mean.
But on the other hand, learning to take a joke when it is a joke is important. You cant get overly sensitive and upset and make a big deal out of something that isnt and shouldnt become a big deal. Even if it annoys you, see where the other person is coming from and if they were saying it just joking around you need to just let it go.
Anyways, coming here is not the best because like half of the forumers havent been in long(er) relationships so they don't really understand what its like