He Disappears For Days at a Time
Unless he died, was severely injured, or got abducted by aliens, a guy who is interested in you will not disappear on you. Frankly, if he does so, he's not worried about losing you. And if he believes you will still be around after pulling a Houdini, he probably doesn't respect you. If he doesn't respect you, you will never commit to you. Let him go, don't lower your self-respect.
So, you just got to treat him like an employee. If he goes ghost on you for a whole day or longer without good reason, that's a no-call, no-show, b---- you're fired!