My father has been married four times now. His third marriage was to a woman who had custody of her two sons. They were 13 and 18 at the time. I was 13/14 during the marriage. I'd spend my weekends with my father and hang out with my step-brothers.
They divorced and have been divorced for several years, now. My ex step-brother (the older one) said that he used to have a crush on me (Before you go bashing and calling him a pedophile, I DID look very, very old for my age. I appeared to be at LEAST 17). Nothing sexual or even flirty ever happened between us. Ever.
Now fast forward to now. I'm 23, he's 28, 29ish. I forgot his birthday. We are all friends on FB, and I can't help but be extremely attracted to him. Not necessarily physically, because really he's not my type in lots of ways, but he has the same exact humor as I and we just seem to, IDK "click" if you will. I feel stronger and stronger about it daily. We don't live in the same state, but I really just feel like we're... I don't know... soulmates. What if our parents married just so we could meet?
ETA: We both have SO's but neither of us is married. We don't talk privately, so there is no emotional affair happening. He messaged me several months ago to catch up after several years and he told me how he felt- that was it. I didn't hint to him about any of my feelings and I never have. I'm not sure if I ever will.
For the record, my relationship is shit right now. We don't even have sex.