Bro it is ultimately upto your feeling from the relationship and whether you can manage your mindset to make it worthwhile for you.
If you can view her as just a piece of meat that you can enjoy within your schedule than why not. Just manage your raw fuck sessions to enjoy her trophy Jap pussy and body around your family and other schedule.
But if you cannot handle the idea that your fine piece of meat fucks other men then have 2 clear choice .. end it now or tell her you wish to be exclusive FB's and see her response.
Having fucked a few Jap ladies over the years, the hot ones always have options, and they manage their other fuck friend dates like an appointment schedule. This stops when you reach BF status, and her 3 holes are for your exclusive use.
One lovely Jap wife who I met with her daughters dated me for 2 years. But due to pandemic, our status changed a bit (long story) from BF to fuck friends. After that I discovered she was pounding her chikopek dance teacher for her daughter who coincidentally is a friend of mine (another long story). Knowing the filthy things she did with me (best sex of my life) I could not imagine her doing the same with this other guy, so I ended it totally for peace of mind.
Hopefully my humble experience is helpful
