Can any DNA, saliva, or blood test detect past sexual contact from 5–6 years ago?

I’m looking for some advice/information about whether this is scientifically possible.

Is there any reliable DNA, saliva, blood, microbiome, or other biological test that can determine whether a person had sexual contact with another person several years ago?

For example, if kissing or sexual activity happened 3–6 years ago, could any test performed today detect biological evidence of that past contact?

I'm specifically wondering about things such as transferred DNA, microbiome changes, antibodies, or any other biological markers that might persist for several years.

I’m asking because I’m trying to understand whether there is any objective scientific way to establish that something happened several years ago, rather than relying solely on someone's statement.

TL;DR: Can any medical or forensic test today reliably establish whether someone kissed or had sexual contact with another person 3–6 years ago?

Summary: I’m looking for a scientific/forensic answer about whether evidence of past intimate contact can remain detectable in the body for several years.