I think it would be best if you avoided him as much as possible while he is there. Do you have plans to do things as a family? Can you let him visit with the kids and go off by yourself for a bit? STBX and I do family stuff together occasionally now (we even went on a short vacation just the 2 of us a while back-- no funny business, though), but back when I was still really raw I had to severely limit contact, or else I'd completely lose it. If you don't feel you're sufficiently detached to spend much time with him yet, don't! I know you're trying to DB him, but it's better to make yourself scarce than to have a meltdown in front of him IMO.
