Why is it so hard to find a threesome?

[Princesslaura]

No matter what, something always backfires I’ve tried the on the spot approach, talking first approach and nothing seems to work, I’m in a straight relationship but have also been with women, he’s loved the idea forever and tbh a woman eating your pussy is like no other but no matter what there has never been any success, even tried the websites and it’s not happening any tips? Or stories of encouragement