Answer
Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
As long as the man you wish to marry is not related to your ex-husband as a father, brother or son either in kinship or breastfeeding, it is permissible for you to marry him.
Responding to your question, the prominent Muslim scholar and da`iyah based in London Zienab Mostafa, states,
The Qur’an states, “Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your father’s sisters, your mother’s sisters, your brother’s daughters, your sister’s daughters, your [milk] mothers who nursed you, your sisters through nursing, your wives’ mothers, and your step-daughters under your guardianship [born] of your wives unto whom you have gone in. But if you have not gone in unto them, there is no sin upon you. And [also prohibited are] the wives of your sons who are from your [own] loins, and that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allah is ever Forgiving and Merciful.”(An-Nisaa’ 4:23)
Based on the previous verse, as long as your ex-husband is not related to the man you want to marry as a father, brother or son by way of breastfeeding (rada`ah), then it is permissible and there is no restriction to marry him. Being just an uncle is not a predicament for marriage. Please, be advised that this could only be done after all divorce consequences have come to an end.
On a different note, you should know that marriage in Islam is not a ritualistic act. Rather, it is a civil ceremony as well as declaration of marriage happens on the community scale.
The agreement of both partners is confirmed and the marriage legislator is just an appointed person by the state to officiate the marriage. So, it is also civil in some away.
Allah Almighty knows best.