Answer:
I cannot recommend any specific books, but I find that studying Psalms has really helped me to understand His love.
It helps to remember that many of the Psalms were written by David during his worst times, when Saul and his armies were pusuring David trying to destroy him. David would begin by questioning where God was and why he was in the predicament he was in – and by the end of the Psalm David would begin praising God because His love just overwhelmed any problem David faced.
Psalms 42:5-8 Why art thou cast down, O my soul? and why art thou disquieted in me? hope thou in God: for I shall yet praise him for the help of his countenance. O my God, my soul is cast down within me: therefore will I remember thee from the land of Jordan, and of the Hermonites, from the hill Mizar. Deep calleth unto deep at the noise of thy waterspouts: all thy waves and thy billows are gone over me. Yet the LORD will command his lovingkindness in the daytime, and in the night his song shall be with me, and my prayer unto the God of my life.
Pastor Brad
ps : read Song of Solomon as well and remember that we (the church) are the bride of Christ. It is a very intimate portrayal of love between a husband and his wife, symbolic of the intimacy Christ wishes to have with His bride in Heaven.