"Adult" relationship - Im so sad. 😓

It really sucks when the person who's supposed to be there for you and who's supposed to be uplifting is the one constantly tearing you down. We have a baby on the way and my fiancé never stops with the insults. He keeps calling me a ho and that I "text" guys and communicate with them when I don't ever do anything like that. He tells me I've been around (when I NEVER EVER have). He constantly makes me feel like I'm "used up" when I definitely know I am not. I love him but if we didn't have a baby on the way I honestly think I would leave because I would never ever put up with this. His words are hurtful but most importantly not true. He's found naked pictures of me on my phone but that's because I had lost 40lbs and felt super confident (the pics are from 2015 when we weren't dating so he assumes I sent them out to people). I, however never shared them with anyone because I just wasn't comfortable ever sharing naked pics of myself with any guy. I know he's not hiding anything from me because he's really open with his phone and I honestly trust him because he's really open about everything. I just thought that we had this beautiful relationship but I'm wrong. I feel like this is verbal abuse some how. He's even going as far as saying that I had a one night stand...because of a poem on a note in my phone which I barely remember writing. I won't let him break me down but it still hurts to be thought of as something that's not true. He is my first relationship, and I waited so long to be in one because I never wanted to be with just anyone but now he's turning into the guys I was trying to avoid and he was never like this. I'm so sad. 😔 I need advice on how to handle this.