For about several decades ago one wouldn't even doubt any other possibility to find physical satisfaction than by having sex with another person. While sex with a partner surely remains on top, solo sex scales up to win an advantage over twosome. The reasons are quite obvious:- Right partner
Later when our choices were more or less determined, which is: you came around the guy or gal next-door, met and moonlight dates would subsequently turn into marriage bedroom.
Now, you have a plenty of guys/gals next door, but you want someone with good looks, intelligence, wit, big heart, money and so on and so forth. Too demanding isn't it? Not really. Of course, you can have sex just with anyone, but who would ever be compared with a person like you? - Less complications
Reality of long-term partner sex is just as follows: fake orgasms, boredom, cheating and all the variety of practices to conceal dissatisfaction. Consequences of one-night stands look even more pessimistic.
With masturbation you don't face all these problems. And for those who say that your hand doesn't give you much of variety, you can simply buy yourself a bunch of sex toys and compare. - Variety of technique
You may oppose that having sex with a partner gives you a chance to experiment with so many techniques. But who said that a sex toy that is rotating, escalating and pulsating with a whole range of speeds inside and outside your spots are worse than a penis or vagina? Besides, you will hardly find a partner to give you double/triple pleasure like some of sex toys do.
However strange it may seem, solo sex becomes a better option for one big reason: the more individualized our lives are, the less we need someone to satisfy our needs that become more and more choosy.
