You can play through a non-NTR Allison route too, as long as you stay confident and keep focused on her through-out. Just don't leave her alone or give any other character the opportunity. Cindy and Emma are too early in development to tell, but likely the same (sort of. At least they're cheating with you). Cherry is an open relationship, at least at first. You can probably avoid all cuckqueening too when playing Lena if female MC getting NTR'd is a concern (though her non-Ian romance paths have been blah up till Holly). But both MCs have been cheated on in their previous relationships from before the game started. You don't play through that part since it's past-history, but it's of course unavoidable.