I disagree with a "wait and see" mentality on this. With a child involved, that takes it out of that realm and into another.
I also agree that it sounds like meth, but I can't say for sure (none of us really can, but we can try to help you narrow it down). If he crashes for days at a time after sleepless nights, then I would bet on meth.
I'm also a proponent of drug testing, (again) especially if children are involved. If it helps YOU hit YOUR co-dependent bottom, then I'm not against it in any way, shape or form, but it has to be for YOU. Addicts will lie to your face when given evidence such as a drug test. So, it won't be to make HIM see what he's doing, but for you to confirm what you already suspect.
What is your objective with confronting the person? And what makes you think this person will tell you the truth? If they are dealing, they certainly don't want to lose their income nor do they want to put themselves in a position to be arrested. So, keep that in mind.
Are there more things you have found? cut up straws, a good amount of plastic baggies all over the place? Going through a lot of foil? Strange smells (from burning plastic to a cat-urine smell)? Strange pipes? Not that I'm telling you to go snoop, but once you realize what you're dealing with, things really start to add up (more often than not in retrospect).
Here is info on what a meth user "looks like":
How To Recognize the Signs of Meth Abuse
Someone else mentioned crack. Here is info on that as well:
Crack Cocaine Use Symptom Signs
And cocaine:
Cocaine Use Warning Signs of Cocaine Addiction Abuse
Good luck, hon. Take care of yourself and that little girl first and foremost.