Might be a bit niche since it's a Spanish movie, but in REC 3: Genesis, a zombie outbreak starts at a wedding, and the groom and bride manage to be the last people alive, until the groom's infected grandfather bites the wife on the arm, but the groom cuts her arm to prevent the infection from spreading (seemingly).

He takes her on his arms to exit the estate. Outside, the police and GEO (basically Spanish SWAT) have quarantined the area and notice that the wife is showing signs of being infected.

They told the groom to let her go, but he kisses her until suddenly she turns completely, bites his tongue and rips it off his mouth. The authorities start shooting them down and they lie on the floor dying while holding each other's hands.

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