You didn't say what kind of smell you were having. Semen has a distinctive smell anyway. In general, smells like bleach result from the ammonias already in the sperm and aren't a problem. A fisy odor can come from a bacterial infection. This can be from the woman or the man. If this odor is noticed after sex, then it can be from the woman, which can be a normal vaginal odor due to the presence of lactobaxillus normally secreted in the vagina. If before sex, you may have a bacterial infection or prostatitis. A cheesy odor in uncircumcised men can be due to a buildup under the foreskin and you need to wash and dry the foreskin more often. Yeast infections can also smell, but these are usually accompanied by pus and redness on the head. Other causes can be from the douch the woman uses, what you ate or drank recently (within the last week), colone, perfumes, vaginal sprays, etc. It could be that the woman is just "smelling" you differently. If the smell continues to bother you are other problems arise, see your health care provider and get checked out.
Hi,Yes go and have a checkup with a good urologists.Good luck.