It's not intended to be a "one & done" game.
Replay, make different choices and see different content.
Indeed, the ability to plough all the women is there by design... So are the eventual consequences for doing so.
That's by choice, quite a few of us mave multiple saves with only 1 relationship per save.
We got told long ago there is no harem so things are going to end badly by sleeping with everyone. It is easier to keep to 1 relationship per save. I've even got separate ones for Katie and Katie with her friends. Jenna solo and Jenna/Jolina etc..
I have a large collection of runs for individual girls (or small groups), and I gave Cheeky plenty of flak for the way the big orgy originally handled solo Lily. So I'm largely in agreement with these sentiments.
But I do think the game is "intended" to be played as the MC chasing all the skirt he can get and putting off the consequences as long as possible. That's why Episode 21 will feature 'movie night' prominently, even though Katie and Jenna just had sex scenes in Episode 20: the point isn't to see more with the individual girls, it's to see the MC weasel his way into each girl's panties while the other two aren't looking.
The way I play, with the MC being more or less above board in his conquests, is done more for replay value and attention to detail: the game needs to offer us the choice in order to justify burning us for choosing poorly (eventually). Our devs are sufficiently perfectionist that they actually fleshed out the alternate routes rather than handwaving the decision with a line of dialog and than forcing the original outcome to happen anyway, for example.
I think there will be offramps from most of the LI relationships as we approach the endgame, and MCs who exit them at the right time can screw nearly all their cakes (pies?) and still keep one (or a couple) of them, too. MCs who sleep around to the bitter end will go down in flames. Those who were loyal throughout will probably get a scene with their true love expressing their longstanding feelings for each other. The 'root' endings for each girl, however, will be written to suggest that the MC has slept around but is now settling down.
That's my guess, anyway.