u need to have an gyn apointment after the first time you have sex. Make yourself an appoinment sounds like an infection either yeast, or BV
You should be getting STD/pelvic exams every 6 months to a year if having unprotected sex. However, an odour coming from your vaginal area is most likely due to either a bacterial infection or just an upset of the ph levels in your vagina. I would see your doctor and have them check if it's a bacterial infection.
Do you use any soaps etc to clean down there? If so, then stop. You should only rinse the area with water (no douching). Vagina's are self cleaning and so don't need soaps etc to clean the area. Anything with perfumes etc in just upsets th ph balance in your vagina and can lead to a foul smelling vagina.
Could be an infection of some sort. Go see your gyno for a pelvic examination. If you're 21 or older, you'll probably get a pap smear, too, which would be a good idea anyway as you are sexually active. During a pap smear, they insert a speculum inside you and then scrape off a small bit of your cervix to test for any signs of cancer. Since you're sexually active, there's always the possibility you've been introduced to HPV, which can cause cancer depending on the type.
Mention what your ex said to you and your gyno will let you know if she notices an odor that might indicate something like a yeast infection or something else.