Maybe they make the dad die in like a explosion in his restaurant and then bobby idk maybe he like breaks up with his sister or the dad get a divorce
Rita and Lynn Sr will not split up. The Rita content is completely optional. Lynn Sr will not know of anything going on between his Son and wife.
Rita won't see it as a betrayal of Lynn because she still loves him and wants to have sex with him... She'll just see things with Lincoln as a new way of "Mother/Son Bonding."
If you don't want to deal with any of that it's why the Rita content will be completely optional.