Here is my thought I have noticed that people often say that in order to keep a marriage going you need to have a good sex life, or sexualy interest your partner. But I don’t see how sex actually has anything to do with love, it seems to me the only reason people have sex is for physical pleasure, which of course has its mental effects, but I don’t see how sex induces love, rather it seems to induce attraction which is confused with love…I mean we see a large drop in the lasting of marriage, is this because it is inevitable that when people rely primarily on sex to gauge love, that because sex is more like a drug , the more you do it the more you get used to it at least with your given partner? So as a result the imphasis that we put on love, effectively treating sex as a symbol of love and thus perhaps idolitrizing to a degree, thinking sex is love, is actually reducing the effectiveness and actuallity of love?
I love more than one person, but there’s only one person I have sex with. So maybe marriage has more to do with sex than love. 
At least now that is the case, has that always been the case, should that be the case regardless. I would say that in a way marriage probably has had a lot to do with sex, but I don’t hink it was a institution originoly created purely for the sake of sex but rather for the sake of procreation and child-tracking: In otherwords back in the day if you wanted to know the child was really yours then you had to have a wife that would only have sex with you otherwsie it would be unknown whether the baby was yours or not, like wise if you said well, thats fine i can just take care of any bebay, you would then run into the problem of people raping your sexual partner in order that there child grows up in your nice wealthy happy good family or whatever.
Maybe marriage is like farming (versus hunting & gathering). For instance, if a man wants a consistent source of sexual pleasure, he has to somehow control the situation. In fact, I wonder if monogamy became more prevalent with the ascendancy of farming.
The issue you raised involves how to save marriage, not how to save Love.
Marriage requires many things unassociated with Love.
One of those things is the reasonable degree of passion required to offset the anxiety beset upon the marriage from outside influences (money being a big one).
Sex is one of the many ways to help defend the inherent desire to maintain the marriage despite the outside adversarial influences.
Sex is proposed as an assistance to save the marriage. But it might also help the Love in that people love based on a balance of their feelings. If they feel only the anxiety from outside influences, they cannot feel the love. They lose their focus and forget the very notion of it. So without sufficient “entertainment” involved, Love, though not directly related to entertainment, can still be lost due to distractions of feelings that eventually erode any thought of actual Love.
Hmmm…
One thing i would wonder is do “groups” that believe in not having sex unless necessary, have longer lasting marriages?
I believe so.
The Mormons would be one example.
Do you propose to substitute sex with Mormonism? 
It just suggests, I think, that marriage might be aided by chasity, or whatever you would call it. i would think the same case is for love, but i wouldn’t say that love and marriage do and most likely have not always gone hand in hand.
There are different theories. It depends on the environment.