Hi Wanna Make It,
Just wanted to say welcome to our forum. I think you're doing fine so far; you're communicating with his lover, etc.
I would straight up ask your partner how much more space he needs. Tell him you feel left behind. Point out that it's been a week so far. Has he stopped contact with you altogether? What is the nature of this space that he's taking?
It sounds like he's been a little distant toward you. Do you know for sure what's going on right now with him and this other lady? Good communication usually requires specifics, so make sure you ask specifically for what you want/need when you talk to him.
I think you'll know if it isn't working. It will be pretty obvious. Don't be too quick to give up on things without doing a lot of communicating (with both him and her).
Each person is different, and each relationship is different. You may find that you're better at managing your time/energy than your partner has been. And he may get better at this over time.
Hope that helps a little.
Love means never having to say, "Put down that meat cleaver!"