Is he losing interest?

My bf of 1 and a half years, we used to have sex once or twice a day, went down to once a week, to once a mth, now we are SEXLESS. Hes always rejecting me in sex, he never wants sex anymore. Even when i take sexy photos, or do sexy moves to him, he never wants to look at it. Yet, his social media is full of half naked women. Women doing sexy dances, rubbing their boobs, etc. And i have caught him staring at them for a long time. Ive talked to him about sex, and he says hes too lazy to go clean himself. Ive talked to him about his social media, and he refuses to talk about it. He seems to be losing interest in me, pulling away. I have caught him saving videos of girls masturbating, rubbing themselves, and ive tried doing what they did, and sent it to him. But he didnt want to even look at it. He says those videos were way before he.met me, and he was only sharing them to his friends. I ask if he kept them to masturbate to it, and he said hed rather do that on his social media. Seems like he.exposed himself to me. So i had a talk w him about.it and he said im just looking for problems and refuse to even talk to me. I have a feeling hes been masturbating to those women he has on social media, rather than having sex w me. Cause theres no way a man would not want sex for mths?? I get horny most times, but get rejected everytime. It makes me feel like hes no longer into me. Makes me feel like i shojld leave him. What do u think? Hes a heathly man, we both are in our 20s. He doesnt drink or smoke, he workouts here to there. So its not a health issue.