Same situation here.
XH is getting remarried next week and whilst I tell myself that she's getting a real prize - a man who lied and cheated and put his 'needs' above his sons, it hurts to see them playing happy families.
I have been on my own now for 3 years, am either at work or with DS, and can't imagine ever being in a relationship again. Whilst that has some benefits, like not watching any of the World Cup
, I do miss the companionship, being cared for, and just the general sharing / helping you have with a partner.
The stress of keeping all the plates spinning does mean I get snappy at times, but DS thinks I am the best mum in the world and that's what keeps me going.