Welcome and thanks for posting your query to HCM.
After reading your brief history the most probable diagnosis I can make is - Chancroid
. This is a sexually transmitted disease
(STD) having short incubation period
(time from exposure to appearance of clinical symptoms) of 3 -5 days. It is characterized by the symptoms and signs stated by you -as multiple superficial ulcers which are painful known as soft sore and swelling of the lymph nodes on one side which are gain painful.
The most important of the advise to you is to immediately take treatment for you as well as your partner to avoid further complications. Take oral antibiotics
such as Ciprofloxacin
1 g daily for 3 days and pain killers under medical guidance. Do not forget to maintain proper hygiene.
If the ulcers were happened due to friction only then the lymph node wouldn't had enlarged. So the possibility of friction ulcer is negligible.You and your partner should also get checked for complete STD profile to avoid any future problems.
With best health wishes.
Dr Sanjay K Kanodia
MD ( Skin & STD)