Hi I amm 28 and married I had sex for about 3 times in a day and what I realized is a tube like swelling around my penis head it is like a tube around my penis head and I don't know what to do no particular pain but I amm worried about this unusual thing... what could be the reason

See a doctor. It may be just your foreskin, or a remnant of it. Doesn't sound right though. Please get it checked out.