How do I get over my ex boyfriend? and I see him and sit by him in classes

There is no fast way of getting over anyone that you shared time/experiences with. Give it time, remind yourself that what ever happened in the past doesn't have to hold you back from the joy & happiness you can have right now. Be gentle with yourself. Time will ease the pain & longing. Keep yourself busy to ease the loneliness.

Ask if you can switch seats. If you don’t want to make it obvious then ask if you can get new assigned seats

I think that time is the best way to get over someone. It is normal to feel lonelier after a breakup. But you'll need to believe that time heals or betters almost everything. Give yourself time to feel the emotions you're feeling and don't push them away. Make plans with your friends and get in touch with them. You probably didn't when you were in a relationship with your ex-boyfriend but now you have the time and you can focus on putting effort into your other relationships! Just don't stray from this path and I'm sure you'll be okay. This is a tough time because you lost someone you love but don't let that define you.

Moving on is definitely not easy especially since you see him every day but most people that I have talked to have said that time truly does wonders on a heart wound. Focusing on yourself and who you were before your ex-boyfriend might help. Focus on the things that make you happy that don't involve him. I know it will be a long journey ahead which is why your friends and family could be people you'd lean on for this time period. It's ok to still be hung up on this relationship, don't give yourself a time limit in healing. Forgive yourself, accept this heartbreak, and let go of the fear and what ifs.