Thank you!! :DD

Okay, lessee.....

(Angst)
Maybe have Connor -who is high, possibly?- come into his girlfriend(reader)'s house (they're both outta highschool). He comes over to the reader and flirts with her, joking, and then have him snap suddenly. As she is giggling/laughing, he takes sudden offense and punches/slaps her before beating her until she blacks out. Then he snaps back to reality, and he's horrified at what he does. The reader, blaming his mood swings, forgives him, and they return to how they'd been.
But, fast forward, and we see that things have continued to go downhill. (Reader) now has to put on makeup on to cover up her bruises. But, being too deeply in love, she stays with Connor (who has since moved in). After she puts on the makeup, she goes to hang out with Evan.
Connor sees them. He goes home and gets high/drunk from the stress of thinking (Reader) is cheating.
When she returns, the house is a disaster, and Connor's in the bathroom with a knife, possibly cutting his arms, or about to slit his wrists/throat.
The reader, distressed, talks him out of it, and he leans against her in a lull from his high. She explains she was simply hanging out with a friend, and Connor seems to calm down.
However, a few minutes later as she's preparing dinner, Connor pins her to the counter, screaming at her accusations of cheating. The reader pleads for him to calm down, that her and Evan are "just friends", but when she says "Evan", Connor grabs her and shakes her harshly.
The back of her head hits the counter, causing her to sob in pain as the back of her head bleeds. Then, blinded with fury still, Connor hurls her across the room before lunging after her again.
He strangles her to death before stabbing her repeatedly...
And he blacks out.
Maybe have him wake up beside her on the floor, cuddling (I imagine Connor as a big ol' cuddler in his sleep and consciousness). Noting she's still "asleep", he giggles/chuckles before kissing her cheek and tickling her (not realizing she's dead). When that gets no response, he finally realizes all the blood and wounds adorning her. He screams, breaking down into a mess and sobbing hysterically.
The reader (as a ghost) watches helplessly, every attempt at comforting him proving futile.
(I write waaaay too much angst myself.... I apologize o(╥﹏╥)o

As for the fluff...
Maybe first have Connor and Evan at some jewelry store, trying to find the perfect couple's set to give (Reader). Evan picks out a cutesy little flower or (favorite animal), while Connor finds a dragon-like set. For a moment, the two argue before deciding on a different one altogether (which is not yet known).
Back at the reader's house, she's doing... Whatever... Online. Just as she begins to wonder if her boyfriends (as she is dating both) forgot her birthday, Connor bursts into her room, a huge-ass grin plastered on his face. Evan follows, beaming excitedly with his innocent little adorableness.
Before (Reader) can say anything, both boys tackles her onto the bed, cuddling furiously. After a while of this, both boys sit up, dragging the reader up with them. Then Connor nods to Evan, who -blushing madly- slowly takes out a small, black box with stars on it.
The reader blushes madly, her eyes wide. Then, slowly, Connor opens it (Evan handed it to him).
Inside is a set of three white gold rings, each with a small, delicate, star-like design inlaid on it with (birthstone) pieces.
The reader, crying, traps the two in a hug. Then, slowly calming down, she pulls back. Connor delicately takes her left hand's ring finger and slips on the ring, which has the reader's name engraved on the inside of it.
Then Connor grabs Evan's ring and slips it on his finger, and the reader does the same to Connor.
For a moment, they all just sit there, holding hands, before they all start cuddling.
They fall asleep with Connor on the left, holding both (Reader) and Evan, (Reader) facing Connor with her arms wrapped around him, and Evan cuddling into the reader's back).

I'm so sorry if I made them too long or detailed!!! ^^;