A Heart-Broken Guy

My driving instructor said he preferred quiet women, and he found the one he loved very much. He picked her up everyday during the on the coldest days in winter and he always treated her nicely.
However, she broke up with him under because of her family’s pressure. He cried and hugged his mom crying for an hour. Others thought that the woman just did not love him that much, otherwise she would have fought fight for him. In my driving instructor’s eyes, his ex must have suffered unbearable pressure from her relatives. They say “karma” exists in every relationship. I believed his next girlfriend will one must treat him the way he treated his ex.

A Heartbroken Guy

My driving instructor said he preferred prefers quiet women and he found the one he loved very much. He picked her up everyday during the coldest day in days of winter and he treated her nicely.
However, she broke up with him under due to family’s pressure. He hugged his mom and cried crying for an hour. Others thought that the woman just did not love him that much, otherwise she would fight have fought for him. In my driving instructor’s eyes, his ex must have suffered unbearable pressure from her relatives. They said say that “karma” existed exists in every relationship. I believed believe his next [one*] must treat him the way he treated his ex.

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*When you use "one" here, it seems to replace "relationship" from the previous sentence. I would recommend changing "one" to "girlfriend" or "partner." My only other suggestion would be to add more transition words or additional sentences that act as links between different parts of the paragraph. For example:

"However, she broke up with him due to family pressure. After receiving the heartbreaking news, he hugged his mom and cried for an hour."

Good job!