I don't see the issue if it's just an option. But if it's forced on everyone, like it happens with Josephine in DAI and where you have no idea if the characters involved had sex or not, nope, thanks. I shouldn't have to count on headcanon to know / to be sure if something happened between my character and his romance or not. What kind of lame thing is that kind of story told ? However as an option, it could be interesting if it would be possible to continue a romance without having necessarily the sexual act. ( for those who'd consider it gladly )
At the same time, while it's something else, I'd like the possibility to have sex with my partner without the whole thing necessarily becoming suddenly overly dramatic. My inquisitor just flirted with Cassandra, being quite romantically interested, yes, but not more than that, not yet in love. He spent one night with the lady seeker, and just after that, the romance seemed already very serious , with some dramatic words quite bold while they just started to be lovers. I wouldn't have been annoyed if the sex scene didn't lock anything.
On the opposite you have no way to tell to Cassandra to slow down without breaking the romance, telling her you don't feel anything for her. You have no choice but to be locked in a very serious relationship without even having time to really fall in love in the romance story or you break her heart. Sex is hardly what make people fall in love, at least not alone. How about I spend more time with a character as my Li first ? Was quite annoyed. I had sex with this character, and my inquisitor is already " I love you ? " and I am forever bound to remain with her ?
What I appreciated with the romance with Morrigan, it's that my character had a lot of sex with her, and considered her as a fun distraction at the beginning of their relationship, being able to stop their little game at anytime, before being really love with her ( the same for her ), their love relationship getting very serious after a while. I like to see when a relationship can evolve, and I felt it was realistic actually. But with Cassandra no time for this. Flirt, she requires me to read her poesy, to kneel before her feets before being possibily available... sex, and just one night changes everything, we are suddenly the best lovers ever, bound to remain together, despite my character having big disagreements over her involvement with the chantry as a divine...
At that point, we should have had the possibility to break up with her if she persists, since her decision also matters for our relationship. Not only she dismisses the feelings of the inquisitor, but we are bound to be passive with only the possibility to whine, instead of choosing ourselves as her lover before such event if we want to be a part of her plans or not. Yes, we can't decide for her if she can be divine or not, but we should be free to decide what we are able to stand or not.
As such, with such annoying example happening, I'd like to remove for once and for all the impossibilty to break up with a character at any point. Unless it has anything to do with important plot story regarding the romance as well, but otherwise, I should be able to break up whenever I want and if I want to, for example because I finally disagree a lot with my LI, whether the sexual act happened or not. It was possible with Miranda in M2.