If you're looking for manga similar to Hebi no Seikatsu, you might like these titles.
There was never a time when they didn't like each other - Minato (Omega) and Jin (Alpha) have sworn to each other to become a "pair". However, when Minato was supposed to go into heat, the doctor reveals to him that the chance of him getting pregnant are close to zero... Minato is shocked that it seems he is unable to bear a child! After all of this, he separates from Jin and they drift apart... 15 years of love between an Alpha who has made a promise to mate, and his childhood Omega friend who's somehow infertile.
Yuzuki has a complex about being an omega male. His beta male cousin, Takuma, is in love with him, but Yuzuki can't accept his feelings. Every day is a bitter struggle. One day, Yuzuki has an encounter with alpha male Asuka, who happens to be Takuma's best friend. It seems that unbeknownst to Takumi, Asuka wants to take Yuzuki for himself...
Kouetsu and Ginga ("There's No Way This is Fate" series) show how to provide first aid to an aching heart. Kouetsu and Ginga are in love with their old friend Yuuzen, who's only interested in girls. The two are overwhelmed by jealousy and loneliness every time Yuuzen heads to a motel with a new girl. They end up finding solace in each other's arms... This prequel takes a look at the depravity that occurred before Yuuzen became an omega.
Haru Mochizuki was ostracized as a child for being an omega, but he was "rescued" by Renji and Eiji Ichijou, two alpha brothers who vow to take him away and protect him. Renji is certain that he and Haru are a fated pair and promises to take him as a mate when they become adults, but years later Renji has disappeared and Haru, believing himself abandoned, has started dating Eiji instead. Eiji is engaged to be married, however, and Haru always seems to come in second place. After being stood up by Eiji in favor of his fiance for the umpteenth time, Haru is shocked when Renji suddenly reappears in his life and tells Eiji that he is no longer needed - he will be taking care of Haru from now on! Renji claims he has returned to finally make good on their childhood promise, but can Haru actually trust him?
"Masa's not here... Should we be doing this...?" Akane is a bespectacled, mobile game-obsessed boy who is best friends with beautiful ex-child star twins Riichi and Masato. The three of them are bound by a deep, dark secret and a pact to help a "friend in need" - both in and out of the bedroom. But when Riichi fails to enter the same high school as his brother and Akane, their relationship begins to change. Can Riichi, who's had feelings for Akane from the start, win against his brother and cross the finish line with the object of his affections...!?