If my husband pays charity, do I also have to pay seperately or is it considered that I have paid also? Can we preay after isha and then wake and pray two rakah tahajjud?

In the name of Allāh, Most Gracious, Most Merciful

Assalāmu ῾alaykum wa Rahmatullāhi Wabarakātuh

It is unclear from your question as to whether you are referring to Nafl (optional) charity or obligatory charity (Zakāt).
If Zakāt is compulsory upon you and you ask your husband to discharge it on your behalf then, Zakāt will be considered as discharged.

If your husband gives Nafl charity on your behalf then, you will also receive the reward of the charity.

It is permissible to pray Witr after īsha and then wake up and pray two Rakāt of Salāh at the time of Tahajjud. However, if one is sure that one will awake at the time of Tahajjud, then only is it preferable to delay Witr till the time of Tahajjud; this was the Sunnah of Rasūllullāh (Sallāllahu alaihi wasalam). Ibn Umar (Radiyallāhu anhumā) narrates that Nabī (Sallallahu alahiwasalam) said:

“The last Salaat performed at night should be Witr”

(Nasburrāya, Pg. 137, Vol. 2 Makiya)[1]

NB. Care should be taken that Witr be performed before the time of Fajr Salaat enters.

Nafl Salāt can be performed in any number at any time. However, one should bear in mind that one should not offer any Nafl Salāt in those times when it is Makrūh to do so.

(Behisti Zewar,Pg.182,Vol.1 Zam Zam)

And Allāh Ta῾āla Knows Best
Wassalāmu ῾alaykum

Ml. Muhammed Sindhi,
Student Dārul Iftā

Checked and Approved by:
Mufti Ebrahim Desai
Dārul Iftā