The biggest problem found around the world are broken relationships. It will happens due to many reason but the most common reason found in recent societies are due to sexual dissatisfaction specially found in woman. If we talk about 3rd world countries where even people unaware about opposite sexes before marriage have also facing similar problem whereas modern world which is full of herbs and open sexual environment are also facing the same problem.
Reason behind this problem is that males are addicted of porn movies. They used to watch those movies daily and their leisure hours. They feel pleasure by watching such movie but the bad impact behind this was that by watching such movies they are loosing their sexual grip and most of them shake their penis and release out pressure from it. After that in future when they are in relation with a woman and switch to bed for love and pleasure. They can't satisfy them just after few intercourse because they need porn movies to get their penis harder to sex with their partner.
It was found in some cases that some partners help male bodies by wearing bikini and lingerie most of the time to make their partners sex organ active. However, they can't continue this habit forever. This is the time where man need some thing extra that can save their relation and make their penis harder when his partner need it.
Sexual satisfaction is the most necessary factor in couples, specially in young ones. Because everyone knows that at the age of sexual awareness no one can hold their child not to be inter-connect with opposite sexes. They are naturally attract each other, get closer, find place, show their bodies to each other and have their pleasure. This is the reason in most countries they give sex education in school were girls are suggested to have birth control pills on daily basis and boy have awareness for use of condoms during sex.
Therefore, for those who don't want their relation to be broken by such a stupid reason they have to spend time in exercise. Need to keep their mind relax. Eat healthy food, take supplements if necessary and give sexual drive to your partner whenever you both need.