How long does it take for an std to manifest itself?

my first pap smear results are coming tomorrow and i had unprotected sex with two dudes on 2013 and 2015 respectively (one time with each). i have been on a relationship with someone since about feb 2016 and we have had unprotected sex a bunch of times (he is clean). I wouldn't want to give him a disease because of the previous dudes and i don't want him to think that i cheated on him recently if i have something.

opinions?