I'm not understanding what is meant by "every time he leaves." Is he gone for a few minutes, an evening, overnight, weeks or months? If you are crying every time he leaves, it sounds like you have negative expectations of what he'll be doing while he's out. Those expectations may be well founded, but if you live in fear of him "wandering off" again, a sustainable and healthy relationship can't exist. The anxiety itself can be a factor in bringing about the event that you fear.
It's possible to love someone who cannot be trusted, but it is essential that you love and trust yourself. In this situation, I believe you need to focus on being grounded in your own strength and self-sufficiency. The only way you can feel "safe" in this relationship is if you feel the inner strength that will keep you from being devastated if he "leaves" again. You sure as hell shouldn't stake your happiness on his "maybe" stability.
You don't have to give up the love, but you can't need him, because he cannot fulfill your need at this time. Maybe in a few weeks, months or years, it will be different. You may find him to be trustworthy again. But even then, you'll be happier if you know you can make it without him. I know that sounds harsh, but it's really the opposite. It's always better to be with someone because you want to, rather than believe you have to be with that person.
I have a cat who hangs around with me all day. She gets into my lap when I'm on the computer. She lays on my chest when I lie down. She even goes to the bathroom with me! She loves me up one side and down the other. But, if I grab on to her as if to hold her in one place, she becomes agitated quickly and struggles to get away. If I insist on holding her for a while, she will eventually start growling, and will run away and stay away, usually for a while.
Some guys are like that cat, always hanging around, until they feel compelled to stay, then they run!
You are in my prayers,
Aaron