If the motor vehicle accident is determined to be 50/50, meaning each person is 50% responsible for the incident, so you use your own Collision coverage for your car's damages, then yes your deductible would be due. Even if you were deemed 100% not at-fault for the accident, when you use your own physical damage coverages of either Collision or Comprehensive you have to pay the deductible amount you chose at the inception of your car insurance policy.
States have negligence laws that help insurance companies be able to determine and divide fault in an accident. There are two main types of negligence laws, one is contributory and the other is comparative. If you live in a state with contributory negligence it means that if you are even slightly at fault in an accident you are not entitled to any recovery against the other driver. So if you live in a contributory state, such as North Carolina, and the accident took place there then since you are partially at fault, half in fact it seems, you could not make a claim against the other party for the portion of the accident they were responsible for.
Comparative negligence is different in that if you are found a percentage at fault then that comes off of what recovery you can make against the other party. For instance in Ohio they have comparative negligence laws that state parties share the cost of damages from an accident in proportion to the share of negligence. A motorist determined to be 50 percent or less at fault may recover their damages minus the percent cause by their own negligence. If more than 50 percent there would be no recovery for losses from the other party.
Negligence typically comes into play when it is contended that two or more parties failed to perform at the standard of the "ordinary reasonable person". For example, suppose one motorist was driving their vehicle too fast in a torrential rainstorm on the highway and hit a car but the motorist in the car that was hit did not turn on their headlight on as they should have due to the rain. In this case both parties could be held negligence in some way and thus both partially responsible.
Since you were in an accident where both drivers are found at fault then it will depend upon the percentage each driver is found at fault as to who pays. If each person is found to be 50/50 as you stated then likely each motorist will be responsible for their own damages. If one driver was more than half responsible for the incident, say it is 60/40 for fault then the person more than 50 percent at fault may end up being responsible and claims can be made against their auto insurance coverages.
Your state's negligence laws should help determine how claims are made in an accident where both drivers are at least partly at fault. If you were 50% at fault and your state allowed you to place your claim with the other party's Liability coverages this would also mean that the other party could place a claim against your Liability coverages. Making claims this way would mean that each of you would only be able to recoup for 50% of your damages from the other's automobile insurance company and then left paying yourself for the other 50% of the damage costs.
Instead to get all of the damages covered it would make more sense to put the claim through your own Collision coverage. By using your own Collision coverage for the damages your vehicle sustained you would get all of your damage costs paid out through the claim, minus your deductible amount.
If you have been in an accident and are 50% or more at fault then making a claim through your own Collision coverages makes the most sense. You can speak to your agent about how to start your claim. If your agent is not able to explain to you what to do in this situation or fulfill your car insurance needs, contact a CarInsurance.com agent and they can explain not only insurance terms and claim procedures but also tell you how they can get you low cost car insurance.