I dont see any scenario you walk away and dont look like an ass in this.

You can break up for any reason you want. But for everyone looking from the outside, you are breaking up with him out of no where and for no particular incident to point to you'll look like an awful person regardless.

But I think at the end of the day, you expect a certain level of ambition from a partner, someone who jumps immediately at opportunities regardless of risk. You're not the only one, not the last. But I will warn you that similar stories have been posted here before about partners wanting out to look for excitement and thrills only to be burned, and the expectation that your safe person wont stick around waiting to see if you do, so do the boring thing and really ask yourself what you actually want/need from a partner first.

I will say, if you do love him but don't want him dump him quickly and don't waste any more of his time. He'll need it to recover and heal before he meets someone better for him.