I'm not sure if you are even checking up on the replies that you are getting, but I just wanted to add some input. It sounds like you have the same discharge problems as I did/do. The milky white discharge is most likely either nothing to worry about.. or it might be bacterial vaginosis. Either way its nothing that is really harmless & if it is BV it is easily treated and isn't technically an STD because you can't spread it.
The thicker white discharge is something I have been experiencing for years now, and I have asked the doctor multiple times and he insists that it is healthy. I have done a lot of searching online and found tons + tons of women that say they have the same issue. This is once again probably harmless but if it really bothers you and makes you uncomfortable the best advice I have is to just "clean" the area around your cervix out with your finger while you shower. That is pretty much where the discharge "hangs out" til after you have sex when it is basically brought out. That might have been too graphic? Sorry if it was, but I know that this was a huge intimacy issue with me until I started doing that daily and it made things a lot better.
Does he use a condom? If he doesn't it could be semen, like the other person said. If he does it could be just your own lubrication. As long as it doesn't have an odor, it's probably just from having sex and your bodies normal way of cleansing out the vagina.
If it has an odor, then I would say you might have a yeast infection. If it turns kind of like cottage cheesy then you can buy stuff over the counter for the yeast. Monostat or something like that. If you are concerned see your doctor.
if u do.. that can be his semen..