Of course they come back for more of what you gave them initially, because they are selfish. So the question is, why do you attract and enter into a relationship with them in the first place? Because I don’t know you, I can only speculate that you may have low self-esteem, an Animus complex in stage one or two, a anxious or anxious/avoidant attachment style, and that you are an unhealthy Enneagram 2 “Helper” type. If that rings true, then you can work on becoming more secure and confident by developing more self-worth.