All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
As you know, masturbation is forbidden. Therefore, such a deed is not a suitable solution to your longing for your husband.
We think that the best solution is to follow the Prophetic Hadeeth that reads: "O young people! Whoever can marry should marry, as it helps to lower one’s gaze, and protects one’s private parts, and whoever is not able to marry should fast, as this helps him to protect his private parts (from committing illegal sexual intercourse)." [Al-Bukhari and Muslim]
So, we advise you to fast more, to be engaged in reciting the Quran and reading beneficial books. If the problem does not come to an end, then you have the right to ask your husband not to delay more than six months. If he does not accept, you have the right to present your issue in front of the courts.
For more benefit on the prohibition of masturbation, please refer to Fataawa 179859, 376036, 87952, and 81167.
For more benefit that a husband is not allowed to be absent from his wife more than six months, please refer to Fataawa 82147, 84073, 85711, and 88642.
Allah knows best.