Need help

I used to be super confident in myself and have an amazing boyfriend of 7 months now and i love him more then anything but my confidence after being with him so long is starting to go away. I gained weight not a lot but a noticeable amount. I was cheated on my past relationship before him and i trust my boyfriend but my habits are killing me to just know he not doing anything wrong. Am i crazy or just need to shut up about this because im really losing my mind.