It is possible and I would even say necessary to have a spirituality outside of church. That's my opinion of what a healthy church is anyway: a collective of uniquely independent spiritual pilgrims. Therefore, it comes down to how to have a healthy spirituality anyway, whether you go to church or not. Being outside the church is a valid and viable way of being spiritual.
Right now I just want to share with you the first and most important step:
Get in touch with your own spirituality! One of the first exercises my very first spiritual director had me do was to go back as far as I could remember and write my "spiritual history". I went back to my earliest years, long before I officially became a Christian, and detected Benediction in my life. During this time I also learned about my mother's prayers over me right after I was born, dedicating me to God. Just like Abraham was blessed before circumcision, before he received the official badge of his religion, so you were blessed before any religion or church laid its hands on you.
When you come to this understanding, then you come to realize that church is simply a community of several communities that you can flow in and out of. They are like pastures where you can go in and out and find pasture. Sometimes in. Sometimes out. Always pasture. Because wherever you are, there your pasture will be provided.