What the hell is the matter with him

So low my partner and I were together a year and a half we split for 4 months and have been back together since November. At first all was great now he's distant he says he's tired from work ect but all I have to do is kiss him and it's like he assumes I want sex and comes out straight away with I'm tired or I don't feel well... Sometimes he says it in the phone before he even comes in. If I try it on I'm knocked back every night of the week. I'm completely devastated and feel so disgusting to the point I sob for no reason out of the blue. Last night I woke up to him poking me in the back with his well you know so thinking he was awake I tried it on for him to shout at me "I've already said no to you once today" I'm just crushed