A temporary separation sounds good at first, but then I think that I would spend the whole time waiting for someone who might not be coming back. It will just prolong the pain I'm in.
Ok first off don't sit around and wait. Live your life. Work on your financials, get a hobby, get out and make some other friends, find what makes you happy without him. My mom used to say to live well is the best revenge. Not that revenge is what I'm selling, just that if you take that space to meet your own needs for a while and live your own life you might find your willingness to put up with this drama greatly reduced. Besides confidence and self sufficiency will make you more attractive you may find someone even better, more mature, and more willing to be flexible. Love hard but never depend on someone to do for you what you should do for yourself. Ask for what you want, take no like a big girl, and ask someone else it's the magic of polyamory.
Loving him and wanting him to be happy is fine. But in a partnership there must be compromise and not just from you. Don't wait for him to meet your need for love. No relationship will succeed until you love yourself enough to be responsible for your own happiness, safety and orgasms.
Is it going to hurt? Hell yeah. Is it going to get better? Absolutely. Will you get the benefit? Only if you give it to yourself. Stand up for what you want but be willing to let it go and move on. Big Hugs and good luck. I hope you get the best of this issue.