Welll......lot of hint from the past (i think)
enjoy to make love with each other => new experience, do it for fun or they just know not long time ago
Is this "happiness" really feel like.... i was confuse a bit when she said that.maybe she just feel happy when they have childs despite the fact they are lesbians....but at the end i realized it's words of regret....they are lesbian....no one will understand what is their happiness .... normal end, sad story sad life