Habit vs personality trait


I want to change something about myself and I’m not sure where to start. I tend to be sarcastic and can also be snappy or harsh. With people I’m not very close to, like at work, lots of remarks I make seem to be seen as funny and witty, not mean, and that’s my intention. My fiancé views them as mean (he’s told me). Sometimes, I get passive aggressive in my behavior with him and I know that’s coming from feeling guarded or hurt or critical, and I agree that I’m being mean. Other times though, I’m just being sarcastic or joking and not feeling mean spirited at all, yet he still gets offended. I know that his feelings are caused by his thoughts and I see that it’s not healthy in our relationship and I would like to change. I want to be softer and sweeter in my life in general. I think these are habits I can change, but I also wonder if this is just who I am…