Hi Thank you for asking HCM I have gone through your query.Loss of erection while presence of partner is due to stress.You should get rid off stress and anxiety for a proper sex.Enough foreplay and fondling by your partner can gives you proper erection.For Premature ejaculation you can try following methods.You can try squeeze and stop technique.You can deviate your thought to something nonsexual when you about to near ejaculation.You can put on a condom or condom with anesthetic which will decrease the excessive stimulation on penis and there by prevent premature ejaculation.If all these not helping then you can approach an Urologist or sex therapist or Psychiatrist for behavioral therapy and medicinal management.Hope this may help you. Let me know if you have any further query.