Firstly you have to define what your personal understanding of what true love is.

When you can define this, then if what you feel perfectly aligns with the way you believe it should feel, then you are feeling true love. True love isnt given by another, its felt by you.

But does this match to what your partner is feeling ?

Perhaps the very fact you can never know for sure, but both rely on mutual trust to believe is the closest thing to the proof of true love.

To finish, I'd just advise you to stop overthinking it, quit analyzing love and just enjoy what you feel with your partner. 

Sometimes, we dont need questions, answers, explanations or even @musing ! We just need to accept and enjoy what is and go with the flow.

Best wishes to you both :-)