Hi,
No matter what your parents disapprove of about/in our relationship, I do not care.
No matter what your partents disapprove of about/in our relationship, I will not care.
Are they OK?
I think you could say either. It depends on whether you think your 'not caring' is how you feel right now, or will start in the future when the parents' views are revealed.
You might also say, depending on your meaning:
No matter how much your parents disapprove of our relationship, I do not care.
Best wishes, Clive