<human>: Trigger warning: Rape, assault, abuse

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I guess I should start my saying that this guy is the first who hasn't been physically/emotionally/sexually abusive towards me.

He cares, a lot. But I don't know how to tell him about what happened to me in the past. I have nightmares about my first boyfriend (who raped me repeatedly during our relationship), I have nightmares about my other exes (all of whom were abusive in some way). When I wake up in the middle of the night, sweating and shaking and crying and he asks what's wrong; all I can tell him is 'bad dream'. 
I'm terrified that he'll eventually leave. He'll get sick of me waking up in tears. So I cling too tightly and I feel like I'm suffocating him. 

I feel like, if he doesn't leave, he'll cheat on me. He'll get bored of the panic attacks I have during sex (even though it's completely consensual with him and I have never once felt pressured into it with him). He'll find someone with less issues. 

Also, I have had therapy. I am on meds for the depression and anxiety.

I know I should tell him, but I don't know how to. He needs to know what happened to me, and my therapist thinks that it'll make our relationship stronger but I don't want to burden him. Please help... I'm so scared to lose him that I switch between clinging too tightly and pushing him away.

Could you distill the essence of the text into 1-3 sentences?
<bot>: Past abuse; hard to talk about with current non-shitty partner. He should know. How do I tell him?