
Both of them are selfish then. Uke want to break up with him just because he THOUGHT seme are better off with a girl. During their argument, if im not mistaken, uke didn't tell the real reason why he want to break up
While seme doesn't want to reveal the past because uke literally doesn't remember him. Since uke don't remember his own boyfriend, means (in seme thought) uke doesn't love him anymore. So, he THOUGHT it's better for uke doesn't remember the relationship between them and just be friend if uke still doesn't remember seme.
In the end, they're selfish for being considerate to each other.

You're missing the point of what I said. I didn't say the uke was not wrong for just dumping the guy without explaining himself. I said the seme was selfish for withholding a major part of the uke's memory. If the uke chooses to dump the guy that's his choice, but the uke was not given a choice in whether or not he could dump the guy again or stay with him it was taken away from him bc the seme decided it was hurtful that he was dumped. Choice being taken away is the issue here.

If the uke choose to dump seme that's his choice. Yes and the consequences of his choice causing him to get into an accident and causing seme to act as if they're just close friends. That just 1 choice and he already used that choice. Just because he lost memory, that's doesn't means the choice is reset like otome game. When uke(still lost memory) asked about the relationship between them, it's seme choice to tell uke or not.
Seme also had his choice taken away when uke want to dump him. If uke communicated properly with seme, both of them can make a choice together whether to break apart or stay together.
But no, uke make his own choice and ran away crash to vehicle. Now both of them are even.
Tbh, it's good thing that Seme didn't tell uke cuz uke might go to hospital again thanks to memories regain all at once and unstable emotion occurred at the same time.

He was begging the seme to tell him about his past, the relationship is important but that is not the issue here. It is not the seme's choice whether or not the uke should get to remember certain parts of his life. The seme as you said did not know why the uke wanted to break up at that point and the uke did not understand fully why the seme was arguing with his dad. In their relationship they did not know everything about each other, which is why it was not okay for the seme to deny him that memory. The seme did not know what memories were linked to their relationship that he was denying the uke from remembering. The uke's maybe going to the hospital if he regained his memory has nothing to do with what was in the story, or what I'm talking about, and even if that was the case the seme is not his doctor; he does not get to decide on the uke's health. We are talking about the power of choice, which the uke took back when he asked his friend to fix his phone and regain HIS memory.
Imagine you have $100 and need to pay a bill, but because your friend noticed that you weren't good with money they took your $100 and would not give it back to you because they didn't believe you had a bill to pay. It is your money!
Consequence of his choice for dumping the seme should be that he gets in an accident and loses his memory??? SCARY
The only choice that the seme lost when he was dumped was to speak his peace in that moment, they could've talked again later. The uke literally lost years of his memory and was just asking the seme to tell him about his past. EVEN??? You can break up and find someone else, but your memory, no that's serious
I think it was unfair of the seme to hide their relationship even after the guy was begging him to reveal their past. It was kinda selfish on his part, but it was a happy ending regardless so alls well that ends well