To keep your life happy, you must choose a partner who encourages you to be your best self. You must find someone who helps you grow and feel free and encouraged. Partners who belittle or restrict you will cause your life to wither; those who are good for you will cause it to blossom into something amazing.
When choosing a life partner, ask the following things:
Do you feel that you can talk to this person without having to hold information back? Communication must be open and flow freely.
Does this person use information he knows about you against you? A good life partner accepts you for who you are and accepts your past; a bad one will use it against you.
Does your partner encourage you to do what you love? A partner who encourages you to follow your dreams, pursue your dream career, is a healthy one, while one who puts his/her needs over yours and asks you to change who you are or put your needs aside is not healthy.
Does your partner speak nicely to you and show you affection? All relationships are different, some more loving than others. But your partner should be kind to you and show you some sign of love.
Does your partner share your interests in life? Kids, marriage, and career are things you may hold dear. A partner who holds different things dear may be a great person, but not right for you. Your interests and goals must be aligned, at least somewhat.