So basically... you're complaining about his lack of sleeping around beforehand to gather experience, experience which he has to gain one way or another, and could make with you. Heck, he SHOULD have gained that experience with you. So why hasn't he? Why have you been together for seven years without tackling this issue in earnest and working through it as a couple. @--Jack-- raises a valid point with the sex therapy suggestion - it's a thing, and it's a thousand times more helpful than dreaming of other dicks.
I'll put it straight: His sexual shortcomings are not simply his own responsibility. They are yours, too. Your posts put a lot of blame on your partner for his life choices / lack of initiative, when honestly, sex is not a solo game. It does not compute that you, with your fantastic past sex life and lots of experience would be unable to show him the ropes for seven entire years. I get the frustration, trust me, but this isn't something complaining on the Internet will fix - proper communication and actual work put into improving things together will. No, I'm not talking about complaining to him for sucking at it, or ignoring the issue for seven fucking years while feeling sexually frustrated.
Honestly, I highly doubt your partner would stick with you for seven years if he wasn't generally happy with you and the relationship, and unwilling to put in the effort required to make you happy in return, as you imply by saying he does not try or has no intention of getting better. You might not see it, but you're basically brushing away the problems in your shared bedroom as his fault, at least in your posts. That simply cannot be the case. I can give you the benefit of doubt, being frustrated isn't exactly the best feeling for self-reflection, of course. But maybe step back from stating online, publicly for all to see, that you crave to screw other people, and try fixing what you got. And for that, communication is key. Not with strangers on the Internet, but with your loving partner. If he stumbles, it's your responsibility to pick him up and show him the way, just as it should be the other way around.
Right now, you're only coming across as a bloody martyr, content with passing the blame along, while priding yourself on "having dealt with it" for seven years. I have experience with martyrdom, of course, and it can be quite cathartic in its own way, but my god, get off your high horse and work on your sodding relationship if you intend to keep it. Shit like that is fixable, given time and working hand in hand. Heck, I have had friends over the years who went to take BDSM classes with their partners to learn the ropes and improve their sex lives and fulfill each other's wishes. Sex therapy, as Jack mentions, may be embarrassing at first, but if nothing else works, that shit might.
Do something to fix that shit instead of waiting for him to have an epiphany out of the fucking blue. Otherwise I can only see you either breaking up before long, or cheating while keeping it from him.
....or maybe he's just gay. Not too unlikely, looking at how you depict him for us.... Wouldn't blame the man, dealing with that pressure.
I'm honestly trying to be constructive here, instead of firing off nukes, by the way. Appreciate it.