To be perfectly honest I don't think Clara ever truly loved Alan. Besides the whole X blackmail thing how often has she even showed she loves him? I'm not talking about her thoughts of "I love Alan". She has been lying to him, keeping secrets from him, getting angry when he tries to help, ignoring his advice, etc. Not to mention cheating on him with a guy she barely knew who happens to be her husbands rival/enemy. I'm not seeing a whole lot of Clara giving a shit about Alan anywhere except for the X threat, which tbh there wouldn't be any mystery to this whole story without X. That's the main reason I stated a while back there is no reason to save the marriage unless your a cuck and that is the only way I see anyone even trying to save the marriage.
Unfortunately Anna imo has been 'poisoned" to the MC, she is one of the "bad guys" since she started working with X to sabotage the marriage. Now she is just another tally in the revenge count as she can't be trusted either. If she had stayed as just trying to expose Clara, I could see the MC being with her when it's all over, but not now after the kiss/door set up. So in essence the only "strong" ending I see would be Alan telling her to fuck off and explaining it was due to her own actions/choices, while having everyone else go down with the bad guy.