First, I am SO sorry you are going through this awful time. I urge you to get tested ASAP - if it has been more than 3 months since you last had intercourse with him, ANY test you take will be conclusive now. The doctors who used to post here stated that even patients who tested positive felt some relief from their anxiety - having a diagnosis is less stressful than wondering, "what if." And, most people do not have HIV, and of course if he is one of the vast majority of people who do not, you cannot have been infected by him.
Even if you DO have HIV, please remember that it isn't a death sentence anymore, and it's very manageable. I have friends who have had HIV for 30 years now, and they are doing just fine. The key is to get treatment as soon as you can, and by not testing, you are potentially delaying treatment that could make a HUGE difference.
Re: the 90's incident. No way. You would NOT have HIV that long and not know it.
Please get tested ASAP. Your odds of being negative are far, far greater than your odds of being positive, even if he did have HIV. The relief you will feel when you get your negative result will be life-changing.
The biggest part of your fear is not knowing. If you were honest with your feelings, you'd figure out that the fear of not knowing your status is what is causing you the highest amount of stress, more than if you actually had it. The way to eliminate this extreme fear is to get tested because then you'll get rid of the extreme fear of the unknown.
Overall your chances of being infected (or rather, for him to be infected and passing it to you) is not that high. It's not like this is such a common disease. I think the chances are much higher that you're fine and not infected at all. So, all you need to do now is get a test and confirm this.