Welcome to life with an addict. We never know if they'll return to using. Quit thinking that YOU will cause him to relapse. If he uses, it's because he wants to use. No one makes another person use.
The fact is, some marriages do not survive when the addict goes into recovery. Sometimes too much damage has already been done. It is possible that you are making things harder than they have to be, at least for yourself.
Are you attending nar-anon meetings? I highly suggest you do so. They can help you learn how to detach from what he does or doesn't do. I hope you'll look into it.