Humans are built with strange behavior mechanisms, such as intermittent reinforcement (aka variable ratio reinforcement schedule).
Inconsistency of love or affection creates a perversely strong psychological bond: seeking rewards from inconsistent sources strengthens and intensifies the subjective value of the reward when it arrives. The doubt you will receive it, despite your efforts, introduces an intense thrill when it is attained.
When easier access surrounds you, yet you choose the method of chance, difficulty, and pain, you obstinately rewire your brain to aggrandize a common reward. You now find joyful pride and a sense of achievement, as if you did good work when you are foolishly returning to a dried-up well.
Yet, in relationships, it is the relief of anxiety in the relationship bond that makes you think it is actually love or affection: relief that you are indeed worth consideration is mistaken for love.