Hopeless and in love

Ugh. I've been dreading this. I really need some advice ladies. My SO and I have been together for almost three years. We love each other a lot and we make it well known to each other. But for the last several months, we cannot.. FOR THE LIFE OF US... Get along. We argue mostly about the way we talk to each other and it's a problem we both don't know how to fix. It sounds easier said than done I feel like to just "talk nicer to each other". We feel so hopeless but yet continue to stay together because we truly love each other and want this to work. We're starting to argue in front of my step son and I really really don't like it. PLEASE. ALL ADVICE IS WELCOME. I just want to be happy again with the love of my life. Picture for attention.