My "sitch" was VERY similiar to this. I hold on to my H, until he "wants" to come back says it's over with OW... until she's pregnant and the last X amount of months in my life come tumbling down to nothing more that lies.
You seem very brave and strong, I am/was/and probably will be a wreck for awhile longer. You should be proud. The thought of my two precious little girls around the OW drives me up the WALL... that's most of the problem.
It always seems sooo tempting to call, write, e-mail (however) to tell off the OW. But that always makes the sitch worse, trust me I know. It's best to keep your nose out and avoid more fighting as much as possible. She isn't winning you are, you realize how strong you are. She may have won the battle, but I bet you'll win the war. That's what I have to tell myself everyday! Try it on for size.
