Is he cheating ?

My boyfriend and I haven't had sex in about four days which is a long time for us. The longnest we usually go is two. So last night I was feeling frisky and thought I'd surprise him so I put on the stockings and garter that I know he loves and my best black lace bra and when he came home from work he noticed and just didn't do anything or really even acknowledge it...usually one look at me in them and he goes crazy. Also he's a minor so legally he can only work four hours a day but his shift will start at 5 and end at 9 or 9:30 and the place closes at 9 yet he doesn't come home till 10:40 or 11:30 sometimes and he only works ten minutes away. Also he's been distant and hasn't been loving on me anymore not just sex but less cuddling and snugggling and hugs and kisses..and I just don't know why to think or do. Please help me out here