How do you know when the relationship is over?

Ive been with this guy for 8 months now and we've been through a whole lot. He was there for me when my mom died and a week later I found out I was pregnant. After deciding not to have the baby it put a strain on both of us. I still love him a lot and he can still put a big goofy grin on my face. I just wanted to hear from you all what you think the moment you know the relationship is over Is