How have you quit J2?

So I haven’t been doing OE very long, literally on my 3rd month. But something I’ve been worried about happening has finally happened. Both of my Js are in the same tech industry, just different parts of it. J1 is a subcontractor and my J2 is an integrator. And as of last week, my J2 has subcontracted my J1 for a project. It isn’t confirmed yet but I’m 98% positive J1 is going to assign the project to me. I feel like I have to quit J2. J2 pays me a bit more, but I absolutely love my J1 and don’t want to leave. So how do I quit a job I’ve just had for 3 months? Clearly there is going to be some feelings and disappointments from J2 and it’s for sure going to come as a shock and surprise. How do I navigate this?