My husband used to have sexual intercourse with me ejaculate and still keep going. now he ejaculates ones and his penis just goes down.what can it be?

Male Sexuality: The mind of the penis can be a mystery to all involved. But, common reasons for decreasing sexual activity or stamina can be fatigue, anxiety, illness, lack of good nutrition, obesity. It can come in many forms. If your husband feels that something is wrong getting in to see his family physician is wise.

See below: It is important to understand that the normal male sexual response is a single ejaculation, followed by loss of the erection. It is possible, but certainly not typical, for a man to be able to sustain erection after ejaculation or to have multiple orgasms. The frequency with which he has sex also plays a role.