Why

I'm pretty sure it's because male omega's can only get pregnant by an alpha, and well, he's a beta, so it's not the same ╮(￣▽￣)╭

Doesn't really make sense though, does it? Kind of a narrow-minded omegaverse

I mean your right, but I just like to think of it like them having "normal" male sex we're males can't get pregnant, thats the only way it can make sense to me , but your right, it's kinda narrow-minded, I really wished he could've gotten him pregnant but sadly that didn't happen

That sounded so wrong, let me say that again, I ment to say that his sperm would only work on females, like normally, if he were to finish inside of a "regular" man, it wouldn't do anything to him.
Although my English is not that good, I hope you csn understand what I'm trying to say.