I want to end my relationship possibly?

So my fiancé and I have been together for 3 years, we have a 16 month old daughter, we rent a home together, and we’re getting married in March. The only thing is that I don’t know what I want anymore.. What sucks is he’s a good guy and a good father. He’s good to me doesn’t cheat let’s me go do whatever whenever. But the things I used to love about him and find cute I find super annoying. Do I love him still yes so much. I just don’t know if I’m in love with him anymore. We fight a lot all the time. We say mean things to each other. I’m not entirely happy and I know he’s not. I don’t want our daughter to grow up the way I did. Back and forth between parents houses. I’m also terrified of being a single mom.. being a mom now is hard and I don’t know if I can handle it alone. I’m really scared of hurting him because I do love him so much but I don’t know if I want him anymore. I’m scared that if I leave him I’m going to regret it and it’ll be ruined.