<human>: 5 months ago I had my heart broken by my first love after dating and living together for 11 months (we were in an Americorps program together).

Went through the typical dumpee grievances, but focused on myself during that time and feel like a whole new man! Gym, healthy living, getting back into old hobbies, etc (all thanks to advice from Reddit too)

My dilemma is that I'm seeing someone really awesome who I met in class during my "dark" period. We recently started dating and hooking up, and I like her, we have a lot of the same interests and whatnot. My issue is this, she "really likes me", and while I like her back, I don't have much of a heart to give at this point. I'm still not 100% over my ex. 

I'm really afraid of moving too fast with this new person and hurting her in the long run. Should I let her know about my ex? My ex and I haven't talked since like November of last year, and while I don't want to be with her again, I still have weird dreams and thoughts of her, and there isn't a day that goes by where she doesn't pop in to my head a number of times.

Any help/advice would be greatly appreciated

Can you give me a shortened version of the text?
<bot>: Seeing someone new who really likes me, yet I'm still not fully healed from a breakup that happened 5 months ago with my first love. Advice needed