Hello,
Welcome to the ehealthforum and I am glad to help you out.
The symptoms that you have described seem like premature ejaculation. It is most often caused by anxiety and too much stimulation. Depending on when premature ejaculation has started, it can be primary or secondary. The treatment of premature ejaculation is having a psychological session with the couple, stop-start or squeeze-pause techniques, desensitizing creams and SRRI (selective serotonin reuptake inhibitors) in severe cases.
Get it examined from a venereal diseases specialist so that treatment, if needed, can be started.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For an exact diagnosis, you are advised to consult your doctor. I sincerely hope that helps. Take care.