A [MF] Dilemma

I don’t even know how to start this and it’s a little bit gross so I’m sorry. But here goes…

It all began several months ago. My partner and I are in our early 40s and have been together for over 20 years. We have 3 kids, all young adults now with their own lives and we have a great deal more freedom than we used to which has greatly improved our sex life. We’ve tried plenty of things, indulged a lot of kinks and regularly fantasise about more. We have a D/S relationship in the bedroom and I have fully submitted to him in all things sexual which up until now has been amazing. He particularly enjoys watersports and I have a strong kink for being humiliated so it works out amazingly.