This is a two partner or maybe more, Let see where it goes.
I been preparing for a self big ritual since the start of October or what some may say "Spooky Season"
I called it the month of ghoulies and ghosty (This is my way of talk to my other half around others that may look down or judge our craft)
So part of the ritual I am doing is cleansing in all terms of the word, I am in full spring cleaning mode, as where a I am we currently in spring. In doing so I got rid/gave of a lot of stuff as old electronics no longer needed, DVD ect. And while cleaning I came across and very old tarot deck of my of 20 years.
Here's the thing I do not used it at, as it's one of those highly commercialized deck that was on Infomercials, I have no spiritual connection to it, maybe a bit of sentimental value cause it the 1st so to magical item my Mom got me. Would the be any negative backlash if I get rid of it(trash it).
As for the other part, the ritual I am doing is relating to my ancestors regarding a project I been doing for over the past 4-5 Years, and I think my intend was so strong that my Uncle(Living) have asking about our ancestors as well. The thing is he's consider the black sheep of the family and will sell out or betray you for a few couple of bucks. Will he's self gain have any affect on my ritual as my ritual is not for self gain but for help to make the work/project bit easier. Basically my intend is to ask for help as it is "ancestor" related but I will still do the hard work. And just need some help where I get stuck.
As far as the tarot deck is concerned, there would be nothing to worry about when it comes to trashing it. It is just paper with some pictures drawn on. Tarot decks are tools we use. The 'magic' and connection comes from the person using them. It is your intuition combined with the synchronicity of the cards pulled and how you interpret their meanings. ...Think of the cards as a mirror; Useful for reflecting on, but they do not generate anything themselves.
Now, if you feel nostalgic or sentimental about the deck you could always give it away to someone else as a gift. That way it might not feel 'wasteful' any more. Or, all else aside, maybe just have a little mini-ceremony to say farewell to the deck if getting rid of it bothers you. Say farewell, sprinkle it with a little salt (for cleansing) or some soil (to simulate a funeral) then wrap it in a clean cloth or bit of Linen (again, like a funeral) then toss it out. Or even bury it somewhere. You do you.
As for the other half, I doubt a working you did for yourself, with intent towards yourself, would 'bleed over' to other people. I would bet that either your interest and his have un-related (but coincidental) sources, or your interest and active searching inspired him to do the same. Unless you specifically called for your family to share in your interest, there is no reason for your working to do so.
Also, Your intent and purpose is yours. His intent and purpose is his. If he is exploring for selfish reasons then that is on him. Not you. You just worry about your own motivations and goals. Why are you trying to take responsibility away from the person who owns it?