This should probably be in General Health but I guess people on this board have more experience of testing 
I have had reason to google STIs and something is confusing me. I was specifically after symptoms and noticed that several may not give you any symptoms at all. So how do you know you have one without getting tested? For example, if you do not know you're married to a lying cheating bastard, why would you go and get tested?
If an STi goes undetected for sometime, will it eventually give you symptoms? If not, does it matter it's not treated?
I have been pregnant a few times - would I have been tested for STIs during any of the anti-natal checks? If so, would they have told me if any tested positive?
If I go and get tested now, and something shows up, would they know how long I had had it for? This question and the one before is because my Ex cheated on me - but it was 20 years ago when "nice" girls didn't need to worry about this sort of thing (oh god, how I wish I'd had MN back then!) so it never crossed my mind to get checked.
If I go to the local GUM clinic, do I have to give my real name or is it all anonymous? (someone we know works in local NHS and could check our records - not that I think she would but the ability is there)
Last one is for DH and may explain the above
Could he get an STI from a blowjob?