After unprotected sex,when would be viable to undergo HIV Test or any STD related test to crosscheck whether we are infected or not ?

I am 33 years old and I’m just wondering if I should wait a few more years to undergo the tests. I know it’s fatal.

it could probably in general amount,,
the cost of the treatment itself.
and is it really a recommended option for those who was diagnosed with that cancer?

if not what are the other best solution for a person to recover.

In the past I have several sexual relations with prostitutes . I would like to go for an STD test because I am planning to get married soon . Right now I don’t have any visible symptoms except an ignorable itching at the tip of my penis. Can someone guide me what kind of tests I need to undergo ? This is to make sure that my partner doesn’t get any STDs because of me .
Thanks Jessica , for your detailed answer , Do you think my penis itching ,I should take it seriously ? Can it be an indication of any serious STD ? I went to clinic doctor told me it is only inflamation , he given ointment ..but doesn’t go way competely .