This mod doesn't conflict with USSEP or Hearthfire multiple adoptions at least. But if this mod won't work with mod conflicts, uninstall this mod for safe.You can't marry Serana with this mod. You can just live with Serana in a default player house.
This mod works after completing the Dawnguard quest line and it is required you haven't get married.

The introduction video: https://www.youtube.com/watch?v=CfwPo_ZNn5k

:: How to enable Serana's dialogue ::
1. Enable this mod and load the game.
2. After loading the game, save and reload the game for enabling Serana's dialogue.
3. Completing the dawnguard quest line is required. Equip "Amulet of Mara" and speak to Serana. If she has a dialogue "Can we talk about marriage?", this mod works properly.
4. Unequip the amulet Mara and speak to Serana at the best place of the balcony in the forgotten vale. If you have already a spouse, Serana never agree your proposal.

:: After the dialogue ::
- Talk with Serana and choose which of the player's houses Serana lives. The default player houses only. If you have children, they can't move to the same house automatically. Tell your children to move too.
- If you want to move to a new modded house, use a mod like "My Home is Your Home" or "Amazing Follower Tweaks".
- She will visit a market or an inn in the daytime rather than stay home all day long when she lives in a city house.
- She will be prepare one random homecooked meal a day, when you ask.
- You can't take "Lover's Comfort" via sleeping, but can take it via the dialogue "I'm glad you're with me" per day, when you are in your player house.
- Serana never open a shop.
- If you want to get married, uninstall this mod. Even if you marry Serana, Serana sometimes misunderstands that you married another person by this mod and she will get angry.

:: Uninstall ::
If you didn't start to live with Serana or if she got angry about your marriage, just uninstall the mod. If you live with her, do the following steps.

1. Ask her to move to her usual place via the dialogue "I'd like us to move somewhere else."
2. Wait for 25 hours via the wait menu.
3. Uninstall this mod.

Remember that you have to uninstall this mod before installing a marriageable Serana mod!

:: Known Issue ::
Serana's AI in each player's house has a little glitch. She will sometimes stand with doing nothing. I'll fix it in future update.


:: All mods list ::
This is the list of my mods uploaded in Bethesda.net. You can download a mod file directly from the list.
https://docs.google.com/document/d/e/2PACX-1vS1U7CCKZP0h5ZZDS6fT38Gr7WVhSK48ztBhQGiAl1_A6I7v5h_j757OLXBQ8SaQZLg4N74snJZY77p/pub