Since both of them have big egos, they will find it pretty hard to take in criticism. They will have to remember not to compete against one other and work together to ensure harmony. If you are still not getting my point, just imagine two rams locking horns and you will get the complete idea. Two Aries can either respect one another greatly or despise each another extremely. There is nothing in-between for them. One of the two Aries will have to relent a bit and give the other a slightly upper hand.
Remember, two lions can never rule the jungle together. However, if they do manage to land up together, ruling in turns can be a very good option. If two Aries manage to reach a sort of agreement in their relationship, you can be sure this will be a lively combo. There will be no place for boredom in their relationship as both of them will be forever active and entertaining. The excitement in the relation of two Aries can hardly be matched by any other signs. The only thing they have to remember is to keep the fireworks under control.