Hello. Thanks for writing to us at healthcaremagic
Unprotected sex is always a high risk in terms of STD's. Ejaculation or not, has no significance.
I would suggest you to visit a sexual health specialist for
counselling and testing at appropriate intervals.
Some STD's may present shortly after encounter e.g
gonorrhea, chlamydia, herpes etc. Others like
syphilis may present later (
incubation period is 3 weeks on an average). HIV, Warts and
Molluscum may remain clinically silent for months before one notices them.
I would suggest a screening test for HIV and testing for Syphilis (VDRL) initially at 1 month after risky sexual contact, this should be followed by repeat testing at 3 months.
Testing for herpes is earliest at 2 weeks after risky sexual encounter.
In addition to testing if you notice any discharge, burning sensation on passing urine, genital ulcers/erosions, warts or growths or inguinal swelling etc you must immediately get it checked with a sexual health specialist.
Regards