Husband is paranoid

Hi I don't know what to do anymore.. My husband is so paranoid he's always accusing me of cheating. He cheated with 2 of my sisters (which I don't speak to anymore) and my sisters best friend. Me and the friend do not get on and she said she done it to get back at me because she thought I was sleeping with her ex (which is not true we were just friends).. My husband is now accusing me of sleeping with his brother because we are good friends and have been for about a year. We constantly argue because he's always looking over my shoulder and accusing me of changing his brothers name in my contacts so in the end I deleted his number just so the accusations would stop. He still accuses me. I have had enough of it but I love him so much he's my first proper love and we have been married nearly 3 years.. I don't know what to do. I have people telling me all the time I deserve better and now I'm starting to think it. I have left him a couple of times before but I always took him back. This time will be the big decision. If I decide to leave this time it will be permanent. What do I do 😭