It affects me in multiple ways, for one, I'm looking for long-term stability, and while I don't think there's anything morally wrong with having many partners, it suggests there is something about that person that does not align with that.
I don't believe people change very much, I believe people think they change very much.
The most chaotic people I know are the ones who "have finally gotten to the right place in their life" all the fucking time.. They're the people who will buy a sweater and declare with a relaxed breath how now their life is finally complete and they wish for nothing further.
From that perspective, I don't believe a person with a large amount of previous partners have "finally found the right one", because, that's what they said the last N times.
Again, absolutely nothing wrong with having many partners, but it's my belief that the many-partner-people are more well suited for other many-partner-people than with me personally.