What is a happy relationship?

People are very different, and what makes one person happy won't be what makes another person happy. You really have to define what relationship you want for yourself. However, if you are asking this question... isn't that a sign that maybe you are not happy?

If the relationship isn't making you happy, then you should leave the relationship (after whatever steps you feel like are worth it to communicate and try to work things out). That's what I would do.

Do you really need the approval of random strangers on the internet? If it isn't working for you, then end it.

A happy relationship should not be work or difficult for either of the people.

If YOU feel that HE does not care, then he either doesn't (too young?) or your expectations are too high (demand too much?)

Look at your own role in all this and see if you are seeing all this right.

Trust, cumplicity, acceptance, good will and mutual cooperation...sharing.
Wisdom is mandatory...