I have major trust issues, advice to fix it?

Please no rude comments that's the last thing I need 😞 but I have bad anxiety which leads to my trust issues with my boyfriend. He's tired that I don't trust him and he wants to feel "free". I know he's a good guy but I don't know why I can't fix these trust issues I have. He's on his last straw and I wanna stay with him. 
Any advice on how to start trusting more??
- advice to keep something to myself when he makes me mad also
Thank youÂ