Black Panther and Storm. And Rogue and Gambit

Namor and Tamara Rahn

Hulk and Caiera

Nightcrawler and Cerise

Beast and Abigail Brand

Blue Marvel and Spectrum

1. T'Challa and Ororo

2. Reed Richards and Sue

3. Longshot And Ali Blaire

4. Gambit and Rogue

5. Wanda and Vision

6. Quicksilver and Crystal

7. Scott and Jean

8. Scott and Emma

9. Thing and Alisha

10. Pete and MJ

11. Pete and Gwen

12. Nathan Summers and Esme

13. Black Bolt and Medusa

14. Tony and Pepper

15. Steve and Peggy

16. Steve and Sharon

17. Thor and Jane

18. 
    

Weirdest thing about Esme and Cable is that while they may be the couple most featured in Cable's series, he's actually dating all five sisters...

Poly

A lot of xmen are currently polyamorous. Besides, the sisters are kind of a hive mind.

Oh god this is as weird as when Rexplode had a threesome with Duplikate

Spider Man and Mary Jane, Wolverine and Mariko, Tony Stark and Pepper

Madrox and Layla Miller

Layla Miller reminds me of of Emma Frost and Kiden Nixon