What kind of values do they have?
Just because a person is not a Christian, doesn’t mean they’re a bad person. You probably wouldn’t be attracted to them if they were but you have to ask yourself, what kind of values and morals does this person have, especially given they don’t have a personal relationship with Christ? Because they don’t have that Christian foundation, their values may not be in line with yours, which can take you down a path of sin, separation and non-forgiveness, only further separating you from Christ.