I dont believe marriage makes people happy.
it does help remove negative emotions. but if you're unhappy and insecure, marriage will not make you happy. it won't change that in you. you'll just be unhappily married.
having a loving and supportive partner does help remove anxiety, stress, sadness and the like, but that's great if you're already happy. happy and miserable people both deals with those feelings. but if you're unhappy for whatever reason, marriage won't change that.