Yeast infection possibilities/concerns

I have had two yeast infections recenty. The first one was about two months ago and the second one was just last week. I know that being on birth control can cause them bit I have been on the same form of birth control for a few years mow and never had any problems. I've read that new sexual partners can cause them and I've had a new boyfriend for about a year now and we are sexually active. I was dating my ex for about five years. Sexual intercourse with him is a lot different. Meaning more fast and rough. I mention this because I've also heard that lack of lubrication can cause them due to the friction But I'm always very wet. Ive also read that semen can bring down the PH levels and make you more vulnerable. Another thing I've just remember is I've recently become lactose intolerant about 2 years ago. I was wondering if that may have anything to do with it since I also read that something in your diet can be the cause of it. I have an appointment with a gyno next week on the 13th of June.