This series is a very slow burn, and it can be difficult to read at times (I often find myself nervous about where it'll go), but it's really a very cool series, and the hero grows and changes over time. Yes, at the start, he is quite possessive and jealous and desperate to make sure that he's the only man in Mika's life. Over time though he gradually changes, working to improve himself, find ways to make himself a better man, and eventually doubt his own intentions. He repeatedly has time leaps, jumping into the future when he's knocked out then jumping back when he dies. The futures he sees have a big impact on him, especially the fourth and most recent future.
Mika has a stalker, who frame Tooru. Mika's friends suspect him due to ways he's known things he shouldn't have (due to his futures). Mika eventually gets scared and runs away in a park, and Tooru chases the stalker who runs after her only to be hit by a truck. In this future he initially has amnesia, and his friend Miyama tries every day to get his memories back. Mika had been raped that night and, while she never saw the rapist, she's accused him repeatedly. When Tooru remembers he recalls a scar on the stalker's arm and an encounter at a summer camp between three schools. He thus goes to a reunion to try and find the stalker, only to see Mika married to another man. After initial fury at the first future where she's married to someone else, he's shocked by how happy she seems and finally realizes that a possessive love like his, desperate to monopolize her and guarantee that she has him first and only, can't bring her happiness and decides to give up on her. He does find the stalker, run away with him, and gain a great deal of information including the fact that said stalker was actually just a scared henchman obeying the real culprit, and soon after said true culprit reaches and kills him, sending him back into the past. In said past Tooru catches the first stalker, and tries to distance himself from Mika so he can set her up with her husband from the previous future. Unfortunately, the stalker eventually opens up to him and reveals that the boy she marries in that future actually is the one who stalked and raped her. As such, now Tooru's seeking to find a way to stop a stalker with a great deal of influence and skill.
So yeah, while it does take a while, eventually the hero does realize that a love obsessed with being his beloved's first and ensuring that she never has anyone else can only lead to pain for her, and decides that if he can't give her the sort of love she deserves then he should perhaps step away and let her find someone who can.