Ok well I found out I dated someone that's spose to be an ancient. Well that person has a part of my soul and I can see that persons old memories is that a dangerous thing for my sanity?

[jordyn]

only if you let it, no one can own your soul, any part of it and if you give it away you can get it back. 

How do you know they're that person's memories?

When someone makes a claim to being anything other than human, usually sets off a red flag in my book.  In all my years i've only had one able to convince me that he might be what he claimed, he had a plausible explaination as to how he came to be in a human body, nothing traditional to claim and had a very good argument for the fact that there were aspects he stated that i'd never heard before.

He ended up getting married and having a kid living happily in utah.

Well one way I know for a fact is i have always found a connection to my memories and the ones I've seen have been unfamiliar to me and seemed distant and I've done research on the names that person gave me. It all checks out and bout the soul I did it for a reason I  know I can get it back at anytime.

[jordyn]

the claim of "ancient" is just way to vague...which ancients?

One of the thousands of cultures, something like the watchers and other theoretical groups, when people start talking about past life entwinements and start playing with souls it always sets off a red flag for me, not only on the actuality of their claim but more so for the many people that use it as a headgame to inflence a person.

I just don't see how this deals with archeology...now if you were asking about the prehistoric sorcerer, the earliest snake culture they found, some fragment discovered giving us a glimpse of lost history or even lemuria or atlantis, it'd make sense. You can learn about how the ancients viewed the human soul, but soul dealings are a supernatural thing, not archeological.

so in answer to you're question...yes, headgames no matter how "real" you believe them to be can be a risk to your sanity, it won't make you crazy but can mess with your emotional and spiritual state quite easily leading into more destructive activities.

look into deja vu.