Even if the marriage is not healthy, even if it is abusive, one choose to be still married because either cannot imagine living by themselves, too tired and just accept that this is fate , or economically dependant (usually woman). 
Hata kama ndoa haina afya, hata kama ndoa yenyewe ni ya mateso, mtu huamua kuendelea na ndoa kwa sababu pengine hawezi kufikiria kuishi peke yake, amechoka sana na anakubali kuwa hiyo ndiyo hatima yake, au ni mtegemezi (hususan kwa wanawake).