Do you mean to say that before 1997, you had normal sexual response characterized by desire for sex, good erection and ejaculation associated with feeling of pleasure. but after 1997, you don't have pressure for ejaculation , it just comes out. there can be 2 possibilities,-one you have delayed release of semen after pleasure (Generally both are associated together), and slowly this pleasure has gone because you tend to focus on your problem, not on the pleasure. Generally this type of delay is due to a urethral diverticulum . It can be easily diagnosed by urethroscopy and treated surgically.
Second is post orgasmic dysthymia
where some people feel sad and restless after sex ,instead of relaxed and high.
Hope this will help
DR SAATIISH JHUNTRRAA