The concept of a soulmate is an ancient and authentic spiritual principle which is part of the yoga system. But that idea has now been supplanted in modern times by something less perfect. When I expect another mundane personality to be the eternal love of my life or provide me with the shelter, protection and happiness I crave, then I will always face disappointment and even unhappiness. It is an impossible hope. I will also be placing an unrealistic burden upon someone else to be my “everything”. That is wrong and a guarantee for suffering. So, who is my ACTUAL soulmate?

Two Birds in a Tree
The Lord and the living entity are compared to two birds sitting in a tree. While the illusioned living entity eats the fruits of the material world, the Lord as the Supreme Soul and best friend witnesses these activities. – Muṇḍaka Upaniad 3.1.1

Although the two birds are in the same tree, the eating bird, the jīva, is fully engrossed with anxiety and moroseness as the enjoyer of the fruits of the tree. However, if in some way or other he turns to his friend the Lord and knows His glories, the suffering bird becomes immediately free from all anxieties. – Muṇḍaka Upaniad 3.1.2

By manipulating a fire-generating stick, great saints and sages can bring forth the fire lying dormant within wood. In the same way, O Lord, those expert in understanding the Absolute Truth try to see You in everything — even in their own bodies. Yet you remain concealed. You are not to be understood by indirect processes involving mental or physical activities. Because You are self-manifested, only when You see that a person is wholeheartedly engaged in searching for You do You reveal Yourself. Therefore I offer my respectful obeisances unto You. Śrīmad-Bhāgavatam 5.8.36