Evil actions start with evil thoughts!
When you first think that your partner is not a good person, then you actually invite your mind and others to find more reasons to prove it to you.
When you want to love someone, you must not think about his/her negative aspects but should focus on the positive ones. Think about all their qualities and you will see that they are not as bad as you initially thought. Bear in mind that there is no end to finding something bad about anyone, let alone your partner. Whether you like to look at the beautiful colour, shape or fragrance of the rose or focus on the sharpness of the thorns, is a matter of your own choice.
Think positive thoughts and see how this affects your relationships, may Allah save us from such falsehood. Ameen!
Source: Muslim marriage