It’s really telling imo when people focus on what is basically a very tiny detail without looking at the bigger picture of his relationship with Rei. Let’s review.
Sure, he remembers a flower. You know what else we see him do?
Seek Rei out intentionally to have children with her and “using his wealth and power to win over her parents”, regardless of what she wanted
Hits her when she stands up for their 5 year old son he was currently abusing, which we can assume was just one example of physical violence
Describes her as weak, insane, and a fool to other people (And that’s the woman he allegedly loves?)
Treats her so horribly that Shoto “remembers his mother crying often”
Played eugenics using her uterus as the place to play god; he refused to stop at anything to get the Quirk combination he wanted. we can infer she did not have much choice in the matter
Shoto describes that she “endured and endured until she couldn’t anymore” which resulted in the tea kettle incidence.
Had her committed under the pretense that she was “crazy”; forcing her to spend 10 years in a psychiatric hospital with no ability to get true healing from her abuse and with the system set against her as a “psychotic” person, and inherently an institution is a removal of rights and autonomy. Despite “feeling bad”, he makes no move to correct the circumstances of her commitment or have her freed
So. Off of the bat, we have financial coercion/abuse, emotional and physical abuse, psychiatric/medical abuse, and reproductive abuse and depending on your definition, marital rape.
Does it, in the face of all of those things, that he did to just her, not including the things he did to her children, truly matter if he was romantic or loved her? Does it? Think really hard about why you’re going to focus on this one small detail in the face of everything else.
This isn’t even including the personal but professionally informed opinion that: if he had ever loved her, or what have you, it would only make things worse. Having an abusive partner be “loving” is a) a literal step in the cycle of abuse and b) makes it much harder to leave or call the abuse what it is because the victim is gaslit into thinking it wasn’t that bad, but they love me, they didn’t mean to hurt me. It often then messes up future relationships because they will associate love with pain, misery and violence.