Do I really need a sex scene?

When it comes to writing Sex Scenes, I'm a panster and I let my characters decide.  I write mostly M/F but some characters in my contemporary novels have wanted more in the bedroom.  More partners, more positions, a little more kink.

Lance anted a threesome with his ex to get to her best friend (F-M-F).

Dani couldn't decide between two men (M-F-M).

The Caulfield cowboys like to tie their partners up and participate in light bondage.

Needless to say, my fantasy characters have much more interesting sexual characteristics.

My werewolves tend to go into heat, and of course with shifters, there's a lot of nipping, biting and general teeth involved. I have a vampire, who of course, takes on blood slaves and a zombie who sleeps (and thus heals), in his case sex is therapeutic. :)

I have a fire fairy who plays with candles and wax, an Atlantian with gills who likes to give blow jobs under water and a fire elemental who can mark you (like a sunburn) when he gets out of control.

What I put the story to paper, sex and what happens in the bedroom tends be what characters are by their nature. 

I was once asked to add a sex scene much earlier in a book, I refused and added a masturbation scene to appease my editor at the time.  I found it to be much more believable for the character than if she randomly called my hero, ran into him conveniently, or whatever plot device I needed for them to get it on.  She simply wasn't that kind of girl.

I just typed "THE END" on a book and am debating an additional love scene for the characters, I have a perfect spot for it and I think it will show readers on their trust issues, but they haven't decided if they'll let me open the door.  Ultimately I let the characters decide what they want share.  After all I'm merely writing their story. :)