DEAR HARRIETTE: I recently put myself out there and started dating again. I have been a single mom for most of my son's life. He is now a junior in college, so I thought it was time. I have used a reputable dating app. Already I have met two interesting guys, but it hasn't turned out very well. In each case, the guy acted like he was head over heels in love with me almost instantly. Wooing me, win…