God is long-suffering towards you, and so you should extend such love to others. You should look within and remember how wonderfully God has dealt with you. The knowledge that God has loved you beyond all limits will compel you to go into the world to love others in the same way.
You may get irritated because you have to live with that unusually difficult person. Life brought you here to exercise your muscles of love. This is your divine mandate.
No love will remain and grow in you unless it is nurtured. Love is spontaneous, but it has to be maintained through discipline.
Love your neighbor as you love yourself!