lbb... i know this sounds mad and it took me 3 babies to get the hang of it but try to comfort without engaging... i find the easiest way is to have aaron on my lap on his tummy, that way i can distract myself with pc or book over him and just be rubbing his back slightly. (obviously not every time the baby cries but times like this when you've done everything possible and they still cry)
he's not crying because of you.... he's simply cross and sore and probably tired at this point and shouting to let you know. you getting upset won't help any of you, it's nothing whatsoever to do with your parenting skills. the best parents in the world can have colicy babies and will have just as much trouble soothing them. just let him cry knowing that mommy is close. sit on the couch with both boys and turn the tv on for ds1 and snuggle him while you let luke cry.
the nurses in the scbu made a really good point about unwell babies (and imo colic is an illness whatever docs would have you believe, anyone who's seen a colicy baby scream in agony knows this) they said that while the mothers instinct is to hold and cuddle and comfort what the baby actually needs and wants is to lie still and be left alone.... that's why tummy down on knees is a good compromise i think... it makes you feel like you're doing something while letting baby get a break from being rocked, bounced, carried, shushed and moved about.... all the things we do with good intentions to make them feel better
have a cuppa and a fag, then set yourselves up on the couch for the day. if he screams he screams, you can still have a nice day cuddling jacob.
you are a good mother.... no-one can cope with months of sleep deprivation and screaming infant without snapping a fair few times.
as for dp.... don't rush into any decisions while things at home are this tough.... see how you feel when luke is feeling better and you're getting more than a couple of hours sleep a night