I've been told by actual medical professionals that women waiting to get treatment for STDs they know they have is a really big problem. A friend of a friend of one of the PAs waited so long to treat the HSV she got from her cheating boyfriend that it spread all over her personal area and she couldn't deliver their baby naturally.
Some people can have these STDs for a lot of years without it causing problems, the main problem that will arise and cause infertility being PID (pelvic inflammatory disease). Now, I've never had any of these STDs, however as any doctor will probably advise before testing, that if you have it, it's best that you try and get treated ASAP, as it's not certain how long it will take for you to get PID. They remind you of risks, every time.
However, normally it takes a fuckin while, the risk does increase the longer you have it. I don't know what it's like where you live but when I do research, Chlamydia is treated by an oral prescription like antibiotics, and gonorrhea is treated by injection and potentially some pills to follow up too.
I think it's easier to get this sort of thing if you're a student. God knows how much birth control stuff is free for students due to the NHS, but I don't know if you're in the US, UK or somewhere else, and what laws apply to treatments for this where you are.
So if trisha got this from a copious amount of partners while working as a sex worker, and not using protection, i really can't feel much sympathy for her in particular. She even said it's preventable from having safe sex, which she clearly didn't do. I won't 100% blame it on her. There's a responsibility of both people involved. Though, no offense to strippers, it's probably not smart to fuck one without protection.
Then again in regards to what you said, if someone trusts their partner enough, and is in a long term relationship, chances of protection being used might dwindle. I think most people have been there. Yes, sympathy for those who (god forbid) trust their partner enough, end up getting an STD and potentially being left with the negative result of that trust for the rest of their life, because their partner wasn't as careful as they were.
I understand that mistakes can be made. I have made quite a few, but even though myself and one other person i know came out of the mistakes clean, I will still tell people they should use protection as they may not be so lucky in the end of it all (case in point; trisha).
However I have never felt sympathy for people who make mistakes but don't learn from them (an example being old college friend I will not name, who had a pregnancy scare, miscarried, and didn't use protection after that either).
Like i said, if your partner says they're allergic to condoms, latex free ones exist. If they flat out refuse, and then try to guilt you by saying you don't trust them, say no unless they get tested and you're on the pill (well, respectively, if you're a girl. no point a dude going on the pill lmao)