So carry this relationship out. Leveling up from kisses to start and as she levels up she can withstand his xp dump bit by bit. Depending on the rate of leveling, once you hit a certain point you might need more points and so on. But eventually they get to the point of having sex. First time she probably make S rank. But then if they are dating and get married and decide they want kids ... And the go at it hard and fucking every day multiple times even if they aren't trying for kids then she probably reaches godhood before their first anniversary after marriage. It would taper off after honeymoon phase. By the time they hit 40 shell be lucky if she gets a level every month.