I hope you are happily married and found your answer
Like the professionals say its perfectly natural nothing is wrong.
Just as u have most women excreting a small amounts of clear fluid during sex and some squirting a cup full
You have women that have a small creamy discharge while others creaming a cup full and more.
You said he is big. Due to this he hits the furthest corner of your vaginal wall, the constant hitting of it creates the cream and if he goes harder and faster u should have a mind blowing orgasm. The cream usually hardens and turns grainy after like u said . that shld not be happening during the heat of the moment. If it is u guys are just too worried about the problem to "creat enough heat". My advice is to let go and give in completely with no worries and push thru till climax
If u guys broke up find u a Caribbean boyfriend. They are very experienced with this as most have big penises and know a lot about this.
If this creamy secretion is naturally occurring, you may still be able to change the scent of it. Try looking at your diet. Even with men, what they eat influences their semen. Maybe theres a certain minerals/vitamins/sugars//wheats in your diet that you can eliminate or replace?
As far as your boyfriend is concerned, if whats occurring is natural it is not the end of the world if hes not into it. The human body has a peculiar way of determining who is sexually and even emotionally compatible. If this is a deal breaker for him then there are many other me who will apreciate you as you are, and perhaps even be turned on by it. The only reason I even saw this post, was because I myself am curious about it, though I've always accepted this as natural in many different women.