1. Your friend dislikes him.
The saying "the onlooker sees most of the game" isn't without reason; often, when you're not involved, your judgment of a person is more objective. If your friends don't like him, then there must be something wrong with him.
2. He doesn't respect your opinion.
When you go to the movies together, does he always decide which film to watch? Are your weekend date plans mostly based on his opinion? Don't think that male chauvinism is a big deal; it clearly shows he doesn't respect your ideas. If he treats small things in life this way, then don't expect to have the freedom to make independent decisions on important matters.
3. He often lies.
Everyone tells white lies, but if he lies frequently and not out of kindness, be wary. You'd better find out his reasons for doing so.
4. Only you take the initiative in everything.
In a relationship, both people need to take action. If only one person is giving while the other is only taking, this unequal relationship is not true love.
5. He is taking advantage of you.
Whether it's physical exploitation, such as sex, or exploitation of your family, such as your family's money or influence, if he shows no concern for you beyond that, it fully proves that he's only dating you to take advantage of you.