My insecurities are ruining my relationship :(

I'm with an amazing guy, like I'm beyond blessed to have a man like him.. That being said, I want to be the best for him.. 
I'm so self conscious about my body and just not being good enough.
I'm a little over weight and my nipples are big :( and omg I've hated them forever 
I had never shown them to any guy 
Except my boyfriend now 
And it like gives me anxiety being with out them covered during sex .. 
I also question everything since my last ex ruined me I swear 
He was a cheater and tried hiding so much from me and it ruined me for real. It's so hard trusting my new man because my ex was such a total scum bag 
I want to believe him that he loves me and only wants me but it's so hard.. I don't know what to do
I'm in love with this man but I feel like I make him feel like he's not good enough because I question everything or I don't give him my body completely.. I don't know 
I know I want him forever and ever
I just need advice on what I can do to better myself and my thoughts about like every thing so my boyfriend and I can grow and love each other forever..