Although having the same sign is almost always synonymous with peace and harmony, in this case it's... another story.
Aries are fiery and passionate people, which is very positive for the future of the relationship, but which could, on the other hand, turn out to be a disadvantage. In fact, integrity could turn into stubbornness and passion into violence. Each of them might try to always have the last word in everything, and this could devolve into a situation of never-ending arguments and constant power struggles. Of course, the relationship will never be boring, promising limitless action and adventure if they put up with the moments of turbulence. Not everyone does.
Another small obstacle for this union is that both the Aries man and woman are independent people in certain aspects of their lives. They will not accept being in a relationship where there is not a certain freedom that allows them to have other experiences outside the relationship. They need to make plans, make new friends, go out to dinner with old friends, and most importantly, their partner cannot be an obstacle for all this.
They want to enjoy all the good things a relationship has to offer, but only as long as it does not endanger their happiness in other areas of life. They trust one another enough to have a relationship based on mutual understanding, respect, and loyalty.
Another problem that tends to arise in this partnership, despite the fact that they are both independent beings, is that one is always more dependent on the other. This causes arguments when the less dependent individual tries to make too many plans without their partner. In this case, the less dependent individual should make an effort to include their partner in some of their plans to avoid them feeling excluded, because this could affect the relationship.
For this union to be viable, in the first place it's necessary for both of them to work on improving their communication. Above all, they will have to learn not to cross the limits, not to invade the other person's territory. They need to allow each other to have a life outside of the relationship, where both of them can gain many good things that will also help strengthen their relationship.
If they manage to overcome these small obstacles and support each other in everything they have in common, they will be able to have a happy relationship full of unforgettable moments because they both have the same need to be loved and a very similar vision of what a life as a couple should be. They will simply have to improve their communication and allow each other to balance life as a couple with life outside the relationship.