Your question clearly implies that you are a Sunni Muslimah and the man you wish to marry an Ahmadi. Ahmadis are followers of Mirza Ghulam Ahmad of Qadiyan who claimed to be a prophet. One of the basic tenets of faith in Islam is that Prophet Muhammad (peace be upon him) is the final prophet and hence anyone who claims to be prophet after him is indeed a false one.

Therefore, according to the consensus of Muslims, they are out of the fold of Islam; so, you cannot pray to Allah to marry him as you are not compatible (in faith).

Therefore, I would urge you to pray to Allah to help you find a marriage partner who would be a source of joy for you in both worlds.