I think everyone is different so there will be no single, correct, answer to this question.
I have not had any therapy and, at the moment, do not wish to have any. It doesn't feel like the right thing to do for me, but I understand that I am in a minority on this forum.
Before I developed PTSD, I had already heard stories of people going through many, many therapists and a great deal of additional trauma, before finding one that is helpful. I was also aware that some therapists will encourage the belief that therapy is the only route to healing (it's what pays their salary after all). Of course, I had also heard of good therapists transforming people's lives in positive ways. When I developed PTSD, I felt incredibly vulnerable and did not want to take the risk of going into therapy. It felt like a further loss of control which potentially put me at risk of additional damage. I decided that the better risk, for me, was to try self-help to begin with. If at any point, I thought that was not working, I would look at other options.
For me, self-help doesn't mean going it alone. I knew almost nothing about PTSD when it first took over my life, so I had very few resources within myself to draw on. I read and read and read. Without the knowledge of professionals and the fellowship of other sufferers I would be in a far worse position now. Someone suffering from my symptoms even relatively recently would not have had these resources to draw upon. I am very fortunate that there is so much understanding now and that there is so much information readily available.
I knew that sharing my experiences would help me to make sense of my thoughts and feelings but, like I said, I was uncomfortable with the idea of talking to a therapist. Instead, I shared my experiences with my husband and later on this forum. In both cases, I have been careful about exactly what I have shared, bearing in mind that the people I was talking to were not professionally trained. For the most part, I have only discussed the impact of my trauma on my life and not the details of the trauma itself. I don't think it would be fair to share details.
It is not a requirement of recovery that all these details are shared, or even remembered. Again, that comes down to your personal circumstances. Some will need to, others won't. If this is something you want to pursue then I would suggest that therapy might be necessary for your recovery.
With my husband I have also made a point of making sure that he is comfortable with the conversation. Initially I was quite selfish with my own needs and overlooked the impact I was having on him. We have both learned to draw boundaries and communicate them with each other better. I also try to always ask if he is happy to talk at all before I start. Sometimes he is not in a position to have a conversation that he would be comfortable with another time.
Do you have anyone in your life who can offer you support? I could not have come as far as I have without my husband. Having his support has definitely influenced my decision to continue self-help without therapy.
Do you have much knowledge of skills to help you deal with the symptoms you describe? I sometimes feel like I could write a book on grounding techniques, mindfulness, breathing exercises, ways to calm my anxiety, recognising triggers, controlling my anger and identifying small steps towards recovery, but that does not mean I am always very skillful at applying them. My husband and the people on this forum have given me a lot of guidance, support and encouragement. I understand that some people find the additional guidance of a therapist very beneficial but, like I said, it's not for me. It's a personal choice (except, like others have said when the individual's judgement is so impaired that they are not capable of making that choice for themselves). What do you feel comfortable with? What do you need? You must do what is best for you.
So long as I am making progress (which I monitor by referring to my list of things I want to achieve and the small steps I can take towards achieving them), and I am not having too much of a negative affect on others around me (harder to judge, but my husband is guiding me), I will not go into therapy. However, I recognise that my approach is not for everyone. Perhaps my healing will take longer. Who knows. But I do know that I am comfortable with my decision and I am making progress.
I wish you all the best in your recovery, however you decide to pursue it.