If your relationship does not already accommodate space, because you as individuals do not make it happen, despite the hustle and bustle of daily life, then it is poor already.
My space is in the shower on a Saturday morning, on the train home in the evening, sometimes on holiday when I take a long beach walk on my own. In between and not separate from normal family stuff. On the blank canvas I was given at birth, I have slowly been painting on the big shapes that define my life, and invariably in between those shapes there are other blank spaces, the little gaps, in which I can dwell and paint other things. These are these spaces, the shower, the beach walk, the summer evening wine outside looking at the space station drift overhead. These do me. I do not need to carve out great waves of unending time, where I have to physically go and explore some great sandy continent with a canvas backpack, or wrap myself up in an intangible blanket of silent 'neglect the family' in the work shed. Or worse.
If he needs to do these things, let him. Let him go. Concentrate on you and existing relationships. If he doesn't come back, life doesn't end. In fact, you do not know what is around the corner. You just never know that.