
I think the ex is not that bad of a person and he is still in love with the uke. He comes back thinking that the uke might still be waiting for him or still unable to move on, so his intention of coming back might to try persuading the uke to go with him(to where he is gonna transferred to).
The reason he dumped the uke was probably because he thought the uke afraid of a long distance relationship, so he offered the uke the choices whether to go with him or to break up. When the fact is, the uke was actually okay with having a long distance relationship with him.
However, the lack of understanding between them made them misunderstood each other's intention.
The ex thought the uke didn't want to be in a long distance relationship and the uke chose not to go with him because he didn't have a faith in their relationship.
Mean while, the uke thought the choices the ex gave him was only to his own convenience and didn't think about the uke's feeling at all. The uke might think the ex already intended to break up so he gave him those two choices knowing the uke would never choose to abandon the place he loved.
Well, this is just my opinion. ┑( ̄△ ̄)┍
Whatever, I still root for the mc. I don't hate the ex but he can't ruin the uke's new love! I hope the ex will get another damn good guy for himself tho. I feel pity for him.

OMGOMGOMGOMGGGG!!!
I LOVE THEMMMMMM!!!!
Yamato is so coooool dammittttt!!!! And sooo nice, so great, so gorgeous I love himmmmm.
Yukio is also soooooo coooool and sooo crazy for Yamato.
And how the fuck can Ai be this cute?! Goshh Ai my sweet heart I love youuuu!!!
I know the story is kinda bitter sweet, but now I'm smiling like an idiotT^T Just can't stop smiling.
Gosh, I'm so glad I read this manga. Bless you author and translators!!

The uke is kinda dumb and stupid. Really.
Imagine if you were the uke, wouldn't the first thing you would say to the seme is you love him? Because that's what the uke regret the most, isn't it?
Why doesn't he try to tell the seme that he doesn't have to hurry to their meeting location (eg. Tell the seme that the uke himself is gonna be late as well so he doesn't have to hurry, or just tell the seme to wait inside some store near where he is and the uke will go meet him there instead. Because the reason the seme was killed in a car accident was because he was in a hurry to cross the road, wasn't it? If the uke try to stop the seme from hurrying to cross the road, at least, even if the seme does die from a car accident, it proves that no matter what he does he can't change the destiny.)
Also, what I find irritating and doesn't make sense is that, normally, if you were to wake up and meet the person who you loved the most, who already died, wouldn't you break out in tears and say the words you most regretted for didn't say? However, the uke didn't do that. He's just wasting the precious time he got.

It seems like the seme's fate is to die that's why the uke has to choose wisely in order to save him.
GIVE ME THE RAWWWWWWWWW!!!!!!!!!