Qur'anic verse (
Surat Al-Baqarah 221):
"And do not marry polytheistic women until they believe. .. And do not marry polytheistic men until they believe. .... And He makes clear His verses to the people that perhaps they may remember."
So either of them can change their religion and can do whatever they want to do. But Allah does not allow this, agay un dono ki merzi. And about that suicide thing Allah says in The Qur'an:
"Do not kill (or destroy) yourselves, for verily Allah has been to you most Merciful" (Qur'an 4:29).
To warn against suicide prophet Mohammad said: "Whoever kills himself with an iron instrument will be carrying it forever in hell. Whoever takes poison and kills himself will forever keep sipping that poison in hell. Whoever jumps off a mountain and kills himself will forever keep falling down in the depths of hell."