So back in April my mom had an affair. It really messed me up. I’ve been with my boyfriend for seven years. This fall I moved back to school for two years of college (we’re doing long distance which we have before). 
I sit beside a male colleague in a couple of my classes, and the most we say to each other is small talk about school and work and that’s about it. We never talk outside of school. 
But lately I find myself obsessing over this person. My brain keeps saying “what if you have feelings for them?” “What if you like them and leave your boyfriend?”. These are horrific thoughts to me as I love my boyfriend very much and see a future with him. But the fact that this guy from school pops into my head and I obsess over the guilty thought, it makes me feel horrible. I’ve been an anxious wreck. I’ve been talking to friends and family about this , including my boyfriend and they’ve all been supportive. My therapist suggested I work on “decatastrophizing “ as well. I.e naming the problem and saying okay what’s the worst that can happen? 

Has anyone experienced something similar to this? Am I going to be okay? Will these thoughts go away? I feel like my own mind is torturing me…