Thank you for your question and patience, I’m Tom and I’ll try to help you.
If your husband were to inform the home office that your relationship had broken down so that you were no longer in a loving married relationship, then the home office would most likely curtail your visa and write to you to advise that you must either leave the UK or apply for another visa.
You cannot unilaterally take your son to another country to live. In order to achieve this you would have to obtain a residence order for the child from court and an order permitted the child to be taken to another country to live. Obviously, your husband would be free to defend your application to court for these orders.
Ultimately, if your child were to remain in the UK whether with (1) you having residence and your husband having contact with him or (2) your husband have residence and you have contact with the child then you would most likely be able to obtain a visa based on your relationship with the child.
However, an application on this basis is not straightforward. You would need a solicitor to act for you and draft the application /supporting evidence.
Take things one step at a time. Seek to have consultations now with a family solicitor and an immigration solicitor, preferably at the same firm. This means that you would probably have to instruct a medium size firm. You can find solicitors near you using the following site:
Once you have had consultations then you will have someone that you can contact immediately if there are immediate developments so you will be well placed to act quickly and decisively in your best interests.
My goal is to provide you with a good service. If you feel you have received anything less, please reply back as I am happy to address follow-up issues specifically relating to your question.