Name changed because this is embarrassing
but I've been here a long time.
I want to preface this by saying I love my DH and I would never cheat on him. He's a wonderful Husband and Father, we've had 15 happy years together and in that time it's never crossed my mind to stray. I know I'm lucky to have him...BUT...
Over the past few months I've increasingly found myself thinking about the fact that I'm never going to experience being 'intimate' with anyone for the first time again. I find myself having ridiculously elaborate fantasies about being with someone (almost anyone!) new, thinking about men I knew in my late teens/early twenties who I could have slept with but didn't and then feeling weirdly sad/regretful. This has never bothered me before, I've never been someone who wanted to play the field even when I was young and, as I said, I wouldn't want an affair (I can't think of anything more stressful!) so why suddenly at the age of 37 is my brain so preoccupied with this?? What's going on with me? 
Could it be hormonal, is this the onset of peri-menopause or something?? It's definitely more intense when I'm ovulating.
DH is very good in bed, so it's not that he's doing anything 'wrong' in that department. We have two small children, demanding jobs and are knackered a lot of the time so it doesn't happen as much as we'd like right now, when we do have sex it's still good, so I don't think it's that. It's not even sex with someone new that I'm obsessing about necessarily, I think it's more the sexual tension that comes before, the possibility of it if that's makes sense? But I don't know how to get a grip and stop thinking about it!
Posting in the hope that someone else has felt like this and it's not just me going completely mad! 