Performance in bed. What shall i do?

I was married on jan 2019 but I had sex with my wife after 10 days...Bcz I didn't have urge to have sex..After that I used to have sex only 3-4 times and then i went to join my job and stayed away from my wife for 4-5 months..Now she came to stay with me but I didn't have any urge to have sex with her..for last one month I didn't have sex with her bcz I didn't have any urge to have sex with her and I am also not excited when she sleeps near me....I am getting hard one while I see porn and also some time mastrubate but I don't have any urge to have sex with my wife..Even if I some time have sex i am not able to last for one month .And I my penis is also not stating erected for more than one min..Previously this was not happening ..I used to last for 5-10 mins..but now I am not able to last..I have no drinking or smoking problem,.But I used to mastrubate 2-3 times in a week by watching porn..Should I use viagra??what shall I do ??plz help..I don't have any disease also...plz