Oh and another thing was he really tried to tell me that maybe our five year old daughter took them and hid them somewhere. That screamed guilty to me!
Yeah.... that sounds like exactly the excuse I might make (when nothing else would make sense). It's an excuse that you can't prove or disprove, and also shifts blame.
I've also wondered if he's relapsed and has just gotten good at hiding it.
Yes. People can be
exceptionally good at hiding addictions (to a certain point), even from their spouse.
I'm dreading having to confront him head on but I know it's necessary.
I know exactly how you're feeling, I've been in this situation so many times I've lost count. Generally on the other end of things, but I still know how it is on your end.
This isn't an "end or world" situation here, but it is something that needs to be addressed sooner rather than later.
He likely needs some help right now that he's not willing to admit that he needs - probably because he doesn't want to hurt you or disappoint you or have you think lesser of him.
To be honest, he's hiding it from you because he doesn't want you to be disappointed or think lesser of him.
The key here is to establish what is really going on with him.
Even if you confront him it's possibly he will deny, deny, deny, deny.
Addiction is such hell for EVERYONE involved.
If it progressed from one or two missing pills here and there to him taking the entire bottle and lying about it - this is a huge red flag that he has fully relapsed and it's about to get a lot worse, that he has lost any sort of control he had over it. This is what I'm concerned about in your situation.
I'm an addict. I know addicts. Taking a few pills is one thing, taking the entire bottle is another and is a more dire situation. A few missing pills is deniable. The entire bottle is not, and this is what concerns me. At a certain point in an addict's mind all consequences go out the window and no longer matter, even if you know you will be caught. It's not a small slip-up, it's full blown addiction at that point.
I don't want to completely write-off your husband. I'm speculating here. But If I had to bet, yeah, I think we know what's going on here.
I wish you the best of luck, I need to go to sleep.