Since when does wanting to make your partner happy, a bad thing?

This actually sounds like a very healthy argument and it tells me that you have the foundations of a strong relationship. You are both looking out for each other's interests.

Let me make his point for him, but using your own framework to understand it. What he is saying in an implicit way is that you will make him happier if he sees you working on ways to raise your own happiness on your own. I don't think you have to necessarily be successful at that either. I think he wants to just see you make the effort.

I won't speculate on his motives, but from your point of view you can motivate yourself by knowing that the effort you put into that he will see and it will improve his satisfaction with the relationship. I realize it might be out of your comfort zone and what you do from habit. This is a great topic for a therapy session as well.