Hi and thanks for the query.
If you have other symptoms like burning in the urine, increased frequency of urine, fever, pain in lower abdomen, then this might be a urinary tract infection.
However, if there are no symptoms then this is most likely ejaculate that went in the bladder, this is known as retrograde ejaculation, and during any episode of ejaculation, some of the semen goes in the other direction in to the bladder and later comes out with the semen.
The best course of action will be to see your PCP and discuss this with him, a urine routine examination will be the best thing to do at this point in time, it will identify what the urine comprises of, pus cells, semen etc.
Let me know if you have further questions.
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