It's a definite concern, and one that needs to be addressed with a degree of promptness and clarity. Sometimes it needs to get painfully explicit into what activities require protection and which don't. Examples would be oral and manual sex.
I am going to be picky with you about the terminology you use, though - and that's not just for the sake of being annoying - there's a reason.
There's no such thing as "Safe Sex" - the discussion you are having is about "safeR sex". The distinction is really, really important. Because there is no definitive "if you do that you will be safe, if you don't you will be at risk" out there, then these discussions can't be about absolutes.
Different sexual activities have different amounts of risk. So this discussion comes down to a risk/benefit analysis. Since the risks are never zero, you need to decide what level of risk you are willing to take on in order to do that activity. Different people involved may have different levels of acceptable risk - none are wrong or right, just different. It is important to explore each of them, and arrive at a place that everyone can agree to and abide by.
Also, please discuss what happens when things don't go according to plan. This would include a condom breaking, or "getting carried away by the heat of the moment". Put procedures in place that talk about what happens if this occurs, and make sure everyone knows. This shouldn't be punishment, it should be about practicalities.
As an example of this latter, we have the agreement in place that should a condom break, then any sex between either of those folks and others will be with a condom. Since the incubation period for most of the STIs is 6 months or less, a full range of STI testing will be done after 6 months and then, assuming it is negative, the fluid bonding can resume.
I'm not saying that this is what anybody should do, but it just shows an example of the logic we used.
"Listen, or your tongue will make you deaf." - Native American Proverb