I have been where you are- in fact, I am there now. It sounds tempting, but it is rarely as easy as the conept might sound at first glance, and the reason we do not do it is because leaving a baby alone to cry is cruel, and teaches them that they cannot trust you to meet their needs. Crying is the only way they have to signal those needs and by ignoring it, we teach them that their needs are not worthy of being met or that we are not consistent and trustworthy. It can damage their brain wiring long term due to excess cortisol (cannot find study right now, maybe someone already liunked? anyone know what i mean??)
That said-- There is nothing wrong with putting a babe in a playpen or safe space and punching a pillow or taking a brisk walk around the house or breathing or making a snack to re-group if you feel that you are getting to that edge on occasion- that is not CIO. CIO is nightly long term and systematic letting a baby cry to sleep train.
I have had to do this recently (take that breather I mean while knowing DS was safe in the other room despite crying-- in fact, i actually had to pack ds up and take him to g'ma and g'pa's house for a night, which i NEVER though i would do, but i needed it for his safety and sanity and my own, for sure)
but CIO is not as simple as they make it seem- while some babes may lightly cry for a few minutes and then sleep, i know my son would scream for hours, getting more worked up, and it would be miserable for us both. i know this based on his response when i have had to leave him in his playpen and leave the room a couple times lately to preserve my own sanity and have a breather/not intentional or systematic CIO. also most moms report crying too, it goes against every parenting instinct, and you will not sleep well with these emotions and feelings. and safety-wise, you do have to check on them. imagine how confused they are, they just want comfort and if they are crying it signifies a need- CIO is denying that need, which is your job to meet. you need to care for your needs too, so if you cannot meet their needs (i.e, if your babe needs to be latched on, bouncing or rocking, and being patted, you may not be able to do this all the time, but at least put music on or earplugs in if needed, and hold or sling them while they cry.
i am there too- join us in the breaking point mamas thread!! but i know that for my son, CIO would hurt his trust in me and the world, confuse and hurt him, and NOT help his sleep. also, most mamas who cio say it is painful for them as well as their babes, and must be repeated each time a transition occurs- teething, illness, a move, a new life situation, a vacation, etc. it just is not as simple as they make it sound.
have you tried No Cry Sleep Solution?? I just ordered and started reading it, and one point the author makes is that we create this false dichotomy of leaving babies to scream for hours until they are too exhausted and apathetic and give up and pass out, versus living with the notion that our need for sleep is not important and we have to live with this the way it is. There has to be something in the middle, a happy medium, where we can gently encourage our babies needs to come more in line with our own, without either completing ignoring theirs (CIO) or completely ignoring our own. I will let you know how it goes for us, and let me know if you have tried it?

And GET HELP- it is amazing what a once a week mother's helper or friend coming over so you can nap will do for your sanity, or more than that if needed. Ask for what you need. I don't know how I would survive right now (and i am just barely surviving) if it were not for a few family members and friends who have really stepped up to make sure I am able to get at least enough sleep and time to regroup to maintain some ability to feel sane and parent my son in the hours where it is just me and him and the going gets rough). ASK FOR HELP and get those naps while you can.
