10 minutes of sex is good. If you want longer sex duration, you may try to learn ejaculation control but it may not be a guarantee.
When a man has sex, the pleasurable feelings stimulate the brain. if the stimulation reaches a peak, the brains end a signal for ejaculation to happen.
So the best way to have more sex time is to learn how to postpone ejaculation. This can be done by many means right from taking mind off sex when ejaculation process stats.. It can be also achieved by wearing a condom or using anesthetic sprays for the penis head.
Next Steps
Meet a qualified sexologist near your place and learn how to postpone ejaculation. This exercises have to be done at masturbation and they cannot postpone ejaculaiton for ever, but it can be controlled to a limit. How ever there are some who dont learn it. These persons who cant learn control cant be helped except using medicines when needed.
Health Tips
Manforse is a tablet for increasing blood flow to the penis. It will not increase sex time.