What does it mean when after sex when you cum it has soap lookin cum?

Not sure. Not sure what one means by a soapy appearance. If the ejaculate has always looked the same "soapy" way for many, many years, and there are no symptoms such as pain, bleeding, foul odors, etc..., then there may not be a disease. If the ejaculate appearance is new, or is combined with other symptoms, one should visit a urologist, who might ask what spermacide/lubricants/condoms/etc. Are being used.