Telling a guy not to look at other girls is telling him to tampen down his sexuality.
A man’s sexuality is a fire. Not a laser beam.
It’s either a big fire, or a small one.
If you succeed in tampening down his fire and get him to self regulate looking at hotties while you are both out, you won’t get fucked as much.
Your own damn fault.
And then it will just be a vicious circle creating larger and larger spirals of insecurity.
“Why isn’t he choking me in bed anymore? Why has it been days since we last had sex? Is he over me?”
Your growing insecurity will quite naturally also be a turn off. Neither men nor women like needy insecure vibes.
You want more sex and him him to be into you more?
Then get him horny IN GENERAL.
There is NO SUCH THING as horny in particular.
If you want a guy to improve his appetite and eat more, you can’t just keep making better and better hamburgers. There is no such thing as focused hunger. A favorite food is as good as you’ll ever get, so grow up.
Make him enjoy the very process of being hungry and eating.
Then be around when he’s ready to eat.
One close mate seemed to take some pleasure in my broad and never ending unfocused sexual arousal, and would even follow behind me several steps sometimes when we went out, in case I wanted to hit on other girls with her there. Kiki. She was anti-jealous, and very secure, and not only not troubled by my broad sexual desire, she harnessed it perfectly for her own benefit.
We both quite enjoyed my unfocused libido – it certainly got very focused upon her for several screamingly intense hours each and every day.
… an old joke about Calvin Coolidge when he was President … The President and Mrs. Coolidge were being shown [separately] around an experimental government farm. When [Mrs. Coolidge] came to the chicken yard she noticed that a rooster was mating very frequently. She asked the attendant how often that happened and was told, “Dozens of times each day.” Mrs. Coolidge said, “Tell that to the President when he comes by.” Upon being told, the President asked, “Same hen every time?” The reply was, “Oh, no, Mr. President, a different hen every time.” President: “Tell that to Mrs. Coolidge.”
In biology and psychology, the Coolidge effect is a phenomenon seen in mammalian species whereby males (and to a lesser extent females) exhibit renewed sexual interest if introduced to new receptive sexual partners, even after cessation of sex with prior but still available sexual partners. The evolutionary benefit to this phenomenon is that a male can fertilize multiple females. The male may be reinvigorated repeatedly for successful insemination of multiple females.
And this advice would only be useful to girls who already score very high on openness to new experiences personality trait. Please see this comment for why much relationship adivce is counter productive and gives too much hope, because it assumes WAY too much capability from other people.