A Unexpected Spark

I never expected to feel this way about my own son, but here we are. My husband and I have always been open, and after our recent divorce, we agreed to co-parent our 18-year-old, Jake. I've been helping him with his college applications, and one night, we fell asleep on the couch while working. When I woke up, I found his arm around me, and my heart raced. I couldn't deny the spark I felt, and it's been building ever since. I'm torn between my love as a mother and this new, confusing attraction. I don't know what to do.