Birth is stressful and traumatic on most creatures on earth... It takes a significant amount of resources from the body of the mother to produce those eggs. If you don't rightfully know what you are doing, why do it at all?
By simply doing research before acquiring a new living creature that's going to depend on you for EVERYTHING, you can avoid some of the most simple mishaps. Snakes are not like dogs and cats that can give you pretty significant signs of anguish and distress. A snake will not cry when it feels unwell, it will sit there and look like it always does, and when it starts to actually give you signs, it's usually far too late for YOU to do anything and you'll need to take your animal to a vet.
It's your responsibility as a pet owner to know what your pet's needs are before you run out and start filling your house with them. That applies to any animal, not just a snake. It's irresponsible and life-threatening to the creatures that you hold under your care to not know at the very least the basics about your animals. IMHO, you've started your research FAR too late after having those snakes for 2-3 years-- without knowing what gender they are, cohabbing them, and overbreeding them.
I'm sorry that this sounds like a vicious tonguelashing, but I'm also sorry that your snakes have had to endure improper keeping practices, too. The internet is a wondrous place full of the right kind of information for you if you just take time out of your day to sit down and look for it. Batwrangler gave a list of books that you can also pick up from any general pet store, if you don't want to search the internet, those books should tell you everything you need.