Ever since some issue between me and my husband our relationship turn plain and sour. Don't get me wrong, he is still trying his best and he didn't have another party too. Wonder is it normal for relationship to turn plain?

It's common for a relationship to flatline especially if something negative happens. Now I'm not too sure what happened between you and your husband but if there is no infidelity or betrayal, then I'm guessing it has something to do with family, money, a misunderstanding or stress of sorts. Have you tried talking things out? I'm guilty of bottling up my emotions when I'm unhappy and I realize that my negative energy somehow seeps into other aspects of life, including my relationship with my partner. Also, if you feel like your relationship is turning plain, that's normal too. It can't always be a fairytale and fireworks everyday -- it takes effort from both sides to make in "not plain". Hang out with other alone without any distractions and talk about it, it sounds simple and relatively minute but talking and communicating your feelings go a long way.