People often tend to overstay in relationships because they are afraid of the guilt that comes with giving up. Know that it is okay to give up on someone and that is also an option. You invest a lot of time and energy in a person, so it becomes difficult to trade all that away. Also, since you are habituated to your partner, it might be one reason you are not able to walk away.  A low sense of self-worth, an overly forgiving nature or hopes that your partner will change someday may be keeping you in a relationship, even when you know it’s toxic.