What Causes Losing Hardness Of Penis During Sex?

i am a male age 32.i am married.my problem is lack of sexual desire,very quick falls,and my penis is not becoming hard when it needed.i have done semenogram test,it shows total count 8.5mi/ml,active motile20percent,sluggish motile30percent,non motile50percent,puscell15-20/hpf.i am not enjoying.this is also aproblem.as my penis is not becoming hard so i used to take manforce100 tablets.under this situation what i have to do?also suggest me few medicines