Originally Answered: Why is it that you can gear up to ovulate without it actually happening?
It could be due to fluctuating estrogen levels. Your body needs to build up a high enough estrogen level to trigger ovulation, therefore our bodies can make many attempts without being able to do so.
There are many factors that come into play when it comes to delayed ovulation. It could be adolescence, breastfeeding, or menopause. Stress, illness, travel, exercise, weight gain or loss, medical conditions, can all delay ovulation. Your body may gear up to ovulate during these times, but these things can delay it. I mean really, your body just sometimes does what it wants to do I guess :) Hope this helps or gives you some ideas.
Same thing happened to me this cycle. I'm going on 2 wks late and was still getting BFN 4 days ago. My fertility monitor detected my ovulation, and has always been 100% accurate for me. I'm wondering if my body tried to O but didn't. I have read that it is not common at all to detect your LH surge and then not O. Good luck to you, and sending you loads and loads of baby dust :)