I understand where you're coming from in saying it's up to him. I don't think that's 'giving him power', it's just the truth. You've made it clear that you'd like to try to work things out and stay together. Now it's up to him to decide whether he wants that or not. That's not 'giving him power', you can't force him to make up his mind, he has to do it himself. The only 'power' you'd be giving him is if you were willing to grovel before him and do anything he asked of you in order to get him to stay, even if you felt it wasn't fair or equal. But you're pretty clear that you aren't willing to do that. The other 'power' you might unwittingly give him is a willingness to wait on tenterhooks 'forever' for him to make up his mind, giving up valuable time you could spend on yourself, recovering from this and moving ahead.
So the only things I'd suggest are that firstly, give yourself a mental timetable for him to make a decision. You don't have to tell him what it is, just that you know when it'll be time to make the decision to end things yourself. You don't want to waste your life. Secondly, that you do have some type of plan for yourself, for a future without him. It doesn't have to be set in stone, just a rough idea of finances, the flat, and what you'd like for yourself.