Incision is Splitting in Center and Has a Yellow Pus Coming out - is This Normal?

I appreciate your concern.  This is not an uncommon complication after a tummy tuck.  This probably represents an area of delayed healing.  I would recommend you follow up with your surgeon.  This is usually treated just with some local wound care and the area should heal up in a few weeks.  If there is any surrounding redness or warmth in the skin this may be more indicative of an infection.  Hopefully this was helpful.Best of luck.  

It’s not unusual for patients to have areas of superficial
wound breakdown following abdominoplasty surgery. These problems occur for a variety of reasons
including infection, poor blood supply and tension on the closure.It’s
not unusual for areas of separation to be covered with scabs and crusting known
as eschar.It’s normal for these scabs
to slowly lift off the wound and reveal a layer of granulation tissue.Once this has occurred, new skin grows over
the surface and the wound edges pull themselves together.In the
vast majority of cases, these wounds heal nicely, but rarely scar revision may
be necessary.During the healing process,
it’s important to perform dressing changes.This optimizes wound healing and minimizes the potential for infection.It’s
important to maintain close contact with your plastic surgeon.Your surgeon should be able to monitor your
progress and take appropriate steps to optimize your wound healing.

Some oozing can occur at this time if the incision hasn’t closed properly, but it is not routine and should be checked out to make sure it’s not indication of a bigger problem. At this time, infection is a primary concern so please make sure to follow proper wound care practices until you can see your surgeon (which you should do as soon as you can).

First, I would contact your plastic surgeon for an appointment to have him/her examine the wound. It is very common to have an open area in the middle of your abdomen after surgery. You do want to make sure that it is not infected. Should no infection be present, then proper wound care should be discussed between you and your plastic surgeon.

This is very common.  That area has the most tension and sometimes spreads or opens.  sometimes a suture will "spit" causing a opening.  This will heal just fine.  Your doctor should be aware.