my partner has no sex drive

Me an my partner very rarely have sex, this bothers me! i was looking through the search history on the computer last week to see loads of porn sites my partner had been looking at for the last 3 weeks (we only got internet access 3 weeks ago) i confronted him about this. he told me that he had been looking at porn because he is finding it very difficult to get an erection. i struggled to believe this because when we have had sex hes always had an erection, but i feel like he doesnt try an he just always says hes to tired or has a headache or its to hot. he told me that he didnt masturbate to the porn, which i also find very hard to believe but we talked about it an he said he would see a doctor. i still was unsure if he was telling the truth, i was very paranoid by now an decided to put my camera recorder where he cant see it to see if he did watch the porn again an get an erection, as he told me he didnt get an erection when he watched it, he was just watching it to see if he could. after talking he promised he wouldnt go on the porn websites again. when i came home from work i looked on my camera recorder to see that only 15 minutes after i left the house for work he had an erection and was masturbating. i could hear in the background that he was watching sky sports and he told me when i asked him that he cant controll when he gets an erection. i asked why he could masturbate when he has an erection when in the past when he has had one an ive been there ive just been told hes not in the mood, to get the reply 'i dont no'! he turned the tv on mute when masturbating but started flicking through channels i asked if he was looking at any porn sites an he said no he was just flicking through, which again i find hard to believe. i feel as though he would rather watch porn or masturbate than make love to me an i feel a very unattractive woman!!! ???