They definitely deserve that. And your right the ex-lover route definitely need more options to be angry of them or just straight up not interact with them. What they did is definitely a big no no for anyone.
Ending 1 is a true happy ending. Because I think the mc will become immortal in the end because he is practicing dark magic and will be together forever with his family.
Would she agree to an exclusive relationship though? The lust part is part of her nature isn't it? Even with love would it really be that easy to just change your nature.