Alexander_the_grey
It would be contrary to what you created to add her in the relationship, I mean you made him see his true desire in the Mirror of Erised and she wasn't included, she never was mentionned as a crush of his, and right now they are having the perfect love story so why had her. But if you thinks it's possible to make it seem logic and want to go with it why not but it's risky. Anyway good work, keep at it I love this story
amelia + sirius fck yeah also make em have twins a girl that takes after her mother and a boy that takes after his father (sirius won't be able to escape happiness) my opinion on tonks is a no due to a great love between aedan and Victoria and adding tonks now would feel a little unnatural and forced because she was not mentioned enough for a proper builtup to it
Really it's up to you and it's your story. Don't deviate from your plan just because of the reader, that can kill the story. Flip a coin. If you like the outcome, do it. If you don't like the outcome, do the opposite. The concern about adding another person to a relationship is a valid one, especially with the emotions and dynamic, but personally I think that is one of your strengths. So I'm less worried about it.
Most stories get ruined by multiple love interest. It’s hard enough making good story with one romance, adding more removes from the Main story to add to the extra romance or makes the romances fall flat since they can’t get enough focus. Just hope you don’t ruin the story wanting to achieve some kind of harem dream.
P.S. At the very least a love triangle. Aeden's interpersonal relationships are all so smooth and solid, and the MC is so unflappable. Adding Nymphadora in contention for his emotions would get him in a scenario we haven't seen him in. His heart pulling him different directions can add drama without feeling like an asspull ala him getting captured and bound despite the immense physical and sensory advantages he has.