Yeah, it sounds like he is offering you your same position back, and has even offered to make some accommodations if you just want to fill in for people who are on vacation (which may turn out to be part time work). But he is not required to create a new part time position for you, if you should turn down his offer. Your old position will be filled by your replacement when/if you decide not to return full-time.

I am going to add another wrinkle to this equation. I know two of the ladies in our office went out on FMLA to have a baby, then decided that they were not returning to work at all. They were required to pay back certain benefits (medical?) they received while they were out, because they did not return to the payroll. I am just throwing that out there. Check to make sure that will not happen to you if you decide not to return full-time. It may be worth it to you to go back to work just for a month or so, so that you do not lose any benefits. Also, if the other girl sees that you are returning to work, she may change her mind after being unemployed for a month and be willing to job share as originally planned.

Ooh, ES you must have been posting when I was. Have you heard anything similar to the situation where the ladies had to reimburse the county for benefits when they didn't return to work?