My BF is not a Christian

Are there any other girls out there who have a s/o that is not a Christian? 
My bf grew up Roman Catholic, but is not pursuing his faith at the moment. He also isnt a virgin, and doesnt mind having sex. (I am still a virgin though). 
I feel so divided between my relationship with God (which has never been super tight) and my relationship with my bf. 
I feel this weird pressure like I can only pursue and please one of them, not both. 
Has anyone else gone through this, or have some advice? 
My bf is the most considerate, loving, understanding, supportive, and genuine guy I have ever met. Ive tried pursuing other Christian guys, but they have all seemed somewhat "stuck-up" in a way. 
Why am I feeling so conflicted and guilty?