Some of the things that can cause no erections are alcohol, emotional things like anxiety, depression, guilt, anger and many of the recreational drugs. Now it's practically nonexistent. It's very common for intimacy in a marriage to take a backseat when children are born. They have found it difficult to come up with a drug that will cause women to lubricate which is tied into sexual arousal, because it is such a complex process. But my guess is that shortly there will be a drug like this on the market for women.
Some physicians also prescribe testosterone for women to increase sexual desire.
Although the majority of women orgasm from clitoral stimulation, it's not surprising or odd that breast stimulation helps you to reach orgasm. Perhaps you could try clitoral stimulation in conjunction with breast stimulation. But overall, I don't see a problem with the concept that breast stimulation is what helps you reach orgasm. Hypo-active sexual desire disorder is a problem where women and men feel a deficiency or absence of desire to engage in sexual activity. Usually it's having no desire to engage in any sexual behavior with any partner.