Say it is indeed possible to pinpoint individual congresspeople, as the grandparent suggested. If some of these congresspeople have a browsing history they'd rather not have made public, identifying them could leave them open to blackmail.
Deny the claim, and then be later impeached for dishonesty.
Admit the claim, and then well, admit it.
IF some of the content is serious enough, it could surely be a foundation of a congressional hearing or perhaps even impeachment process? How can he respond to the questions there?
In any scenario... I can't see how he could "win" this? (Unless he is really innocent of anything questionable of course)
Which is why Trump probably won't be impeached, or even seriously censured - doing so would only cause an insurgency by Trump's supporters and it would weaken Republicans in the face of the Democrats. It would be suicidal.