WHEN IS IT TIME TO LET GO?

okay so of course I was very sarcastic when I title my blog site as my wonderful life!
Im 27 years old and have been in the same relationship for 5 + years, but now I'm wondering if it has even been worth it.
don't get me wrong, I do believe in love and I love my other half, but being in love is becomin obsolete to me. I feel kind of guilty for feeling that way, but its the truth.
I have been thru hell and high water for this person, preganancy scares, and even a half planned wedding! ( told you it was a lot)
But when is it time to let go?
Happy days are a distant memory and its more like we are roommates than soulmates. I have tried so damn hard to be everything to this person but it seems my all still is not good enough.
After all of these years, it's hard to just turn my back and walk away. There are kids involved, time, money, all of the above and more.
What do I do? Talking doesn't help, Ignoring it makes it worse, and Arguing ...well we all know how that goes.
Eventually I know the answer will come to me, its just hard to see the truth when you are wearing shades.