You're so wise to be looking at your relationship this way.
In my experience, it's important to stay conscious. Recognize what's going on inside of yourself when habitual behavior sneaks up on you - when there are reactions which might lead to suspicions, anger, feelings of being hurt in some way, maybe jealousy or envy. Those kind of things. (Everyone has unresolved issues which get triggered when their demons are confronted.) Recognize he's not responsible for any of that in you, and you're not responsible for the same kinds of things he might be thinking or feeling.
You're two individuals having relationships with yourselves which you're sharing with each other. Share your thoughts and feelings without pointing fingers at each other. No judgements and no criticisms will steer you away from slipping into codependency and old habits. Good honest, sincere communication is key. The intimacy found in sharing your deepest feelings about anything - loves, fears, doubts, plans - will only bring you closer.
Your wanting to slow things down, is very smart. Sometimes going slowly is the fastest way to get somewhere. It helps to keep at bay any habitual behavior, and to keep consciousness and sensibility from being run over by the warm fuzzies. Form without content gets old very quickly. Check in often with yourselves and each other to keep the foundation of your relationship fresh.
It sounds like you've got a great thing going, and I think you're both fortunate to have each other in your lives.
All The Best.
