Do you marry before the game ends?

[RubTheDuck]

Some Rune Factory games wont let you marry until you beat the whole thing.

[Algester]

you "can" marry certain character at certain parts of the game
just to give you an overview
Unlock Flower Shop
you can marry Ludmira, Murakumo, Cecil, Scarlett, Fuuka
Finish Belpha Ruins 2nd Loop
you can marry Priscilla, Beatrice and Reinhard
Unlock Radea (this is much more specific to the dungeon where she starts living in town)
Lucas can be married
Finish Bandit King Dungeon
Ryker can be married

[HeraldOfOpera]

Note: "Bandit King Dungeon" almost certainly refers to the second such thing, because the main reason to romance him is to discover what the heck he was even doing there.

[Endora]

As soon you unlock Radea you can marry if the other conditions are met. If not, you can stop progressing the history until you met said conditions. If the history avances until Radea leaves the city, you'll need to wait her return after the endgame.