I think this depends on your circumstances and your child.
My DS is 3 and has been on holiday with his dad, so has been away from me for a week, he has also stayed with his dad when I had to have 5 nights away for work.
However DS has been seeing his Dad every other weekend (2 nights) for an awful long time now.
Would there be any contact in between times? It seems like a long time, if not. What would happen with childcare/ school?
Perhaps, if there are no other concerns but the length of time, you could agree with your ex to work up to this length of time over time so that your daughter gets used to it?
However, if you have concerns about the length, then you should feel able to air these and have a proper discussion with your soon to be ex.
It should really be a negotiation between the two of you, based on what is best for your child and what you are both able to commit to around the other commitments in your life. But if he is getting nasty perhaps mediation would help.