Yes you can have a STD without symptoms. 1 1/2 years would be long time to carry around a STD without knowing anything but possible. Pap's often don't test for STD's such as gonorrhea and chlymida because the test is unreliable. If you gave him oral sex then he could have NGU which is common because it is bascially just bacteria found in the mouth which causes the infection. Or it could be nothing at all.
Update us on your test results when they come in.
yes it can my mother had clamedia for over two years and developed cervical cancer and died it was a contributing factor