Totally in love again but after two cheaters

After two failed Marriages and both ended up cheating on me and abuse I fell in love again. At first we had sex 3 times a day 4 years later and 1 child we barely have sex once a month. He is a roofer and gone from 5am until 6pm or later. And yes he is really working takes his work truck which has a GPS and can only use on work assisngments and has a helper (guy). He is an amazing guy who loves his 2 year old comes home after work everyday and doesnt go out unless its with all of us. I have kids from previous marriages that he is aweome with and loves. But for about a year now we have been have sex once a month. Im 36 and am like craving sex. I know he isnt cheating but when I confront him he said he is tired from work or uses our daughter as an excuse. So then my thought go to cheating even though i know he isnt. He tells me im his whole world. Im just craving sex and he isnt anymore. what do I do? I love him with all my heart but worried my fears from last two marriages Ill push him away. Its causing me Stress depression and sick. Help Please