A Sword Master Childhood Friend Power Harassed Me Harshly, So I Broke Off Our Relationship And Made A Fresh Start At The Frontier As A Magic Swordsman summary:

The power harassment from Alfine ー his girlfriend and childhood friend ー who is the same age, grew up with him, and became adventurers together, is painful. She is a peerless beauty, a person with the title "Sword Master" and called the "Flawless Sword Goddess," a capable woman with achievements recognized by the kingdom and rewarded with appointment as a knight and became a noble. On the other hand, he is treated as that capable woman, Alfine’s accessory, gets abusive language hurled at him by her, and suffers from her harsh power harassment and insults to him as an adventurer, resulting in him losing his dignity as a man and as a person He has resigned himself to spending his daily life in the position of a lover-caretaker.However, changes came to that daily life. Alfine, who becomes busy as the kingdom's knight, often is unable to take part in adventures. As a result, the times he takes requests alone increases, and he is able to regain his lost dignity. Then he becomes aware of the abnormality of his circumstances. So, to regain himself, he chooses to leave her and her repeated power harassment behind. In addition to all of the equipment he has received until then, he returns his sword, one of a pair they had exchanged when they became adventurers. Declaring that they are over, he leaves the place quickly."From now on, I will change my name and appearance and live freely."As soon as he decides that, everything goes well. When he realizes, he is praised by the people around him and is the greatest adventurer on the frontier. What's more, he got a proposal to marry the frontier lord’s daughter from a female adventurer.