What Causes Swollen Labia Minora And Frequent Yeast Infections?

hi my name is clay. me and my wife have been married for 8 years. The last 3 months I have noticed some changes in my wifes vajina mainly in her labia minora. Her labia minora is swollen and sometimes it is purple. I have read many articles about this and in almost every article I read they say the swelling of the labia minora is due to sex. I have musclar dystrophy and have been in a wheelchair since I was 10. My wife and I probaly have sex once a week and when we do there is not much intercorse because of my disability. The main thing we use for sex is a vibrator. I have not noticed her vajina to change like this after using the vibrator for 8 years of marriage. I would like to know if an infection or some other medical thing can cause this or is it because she is having sex the normal way with another man. She also has a lot of yest infections, and right before I notice the change in her vajina we used the KY intence gel maybe 5 times in the last 3 months. email YYYY@YYYY