I find that different astrologers have different opinions about Vertex.
My personal experience of Vertex is that strong connections seem to make me jump into a relationship. It seems that it is when someone´s planet hits my Vertex/Antivertex and when there are strong Vertex connections in the composite that I feel it the most. I get the sensation that I just have to be with the person and I quickly become serious with them regardless of red flags, fears and barriers.
An ex of mine had Vertex 3 degrees from my Mars. His Antivertex is exactly conjunct my Moon. My Uranus is exactly conjunct his Vertex/Venus. In the composite chart Vertex is 1 degree from the Dsc. We had an unstable and electric (Uranus) and emotional (Moon) relationship. There were obviously many other important connections as well. We became serious quickly. There was intense passion. We broke up after three months.
Another ex of mine had Chiron/Vertex exactly conjunct my Moon. My Chiron is conjunct his NN. In the composite Chiron is 2 degrees from the Dsc. We both have Yods pointing to Chiron in our natal chart and we had a Yod pointing at Chiron in the composite. He was very in love with me from the beginning and he pursued me even though he felt very nervous around me. I didn’t feel the same for him. I was very frustrated since I could feel his Chirotic wound while he was in denial and only interested in cars and beer. In my natal chart I have Chiron exactly conjunct Mercury, I am constantly focused on analyzing and connecting to my wounds.
My father´s Sun is exactly conjunct my mother´s Antivertex and her Uranus is exactly conjunct his Antivertex. They have Chiron and Vertex conjunct the Dsc in the composite chart and a Yod with Sun at the apex in the composite. They have many heavy Pluto and Saturn aspects. The first time they met my mother knew within an instant that he was her future husband. They had a very destructive on/off relationship during many years.
My mom have told me about the most passionate relationship of her life. They have no Vertex conjunctions in the synastry chart. But they do have Mars/Neptune/Vertex conjunct the Dsc in the composite.
I have many more examples so Vertex is definitely something I use even though I haven´t read a lot about it. I don´t know if its a coincidence that it shows up in the important relationships I have analyzed.
I see several men from my past as soulmates. A man with Sun exactly conjunct my Dsc was the biggest challenge of them all. However, I think that it is important to understand that soulmates enter our lives to mirror us and trigger us so that we can evolve. To me it seems that many people have difficulties with being with someone they have a strong chemistry with. People long for someone to reach their core, but when it happens they can´t deal with everything that is brought to the surface without feeling repulsed by the other or feeling so fearful or hurt that they push the person away. Some people go through life taking out their issues on other people, if they meet a soulmate and things from their inner depths start to surface they may get really destructive and pour it all out on the partner.
These are just my observations and I may be right or wrong