You love a nothing when you love an ingrate.

Affection given to someone who never returns anything eventually has nowhere to land. It is not that they owe you a payment. It is that a relationship needs some traffic in both directions to be a relationship at all, and without it you are attached to an idea rather than a person.

Look at where most of your effort goes and whether anything comes back from it. Try giving a little less for a while and see whether the other person notices. What they do with the space will tell you what you have been dealing with.