Had an episiotomy as part of ventouse delivery when I had DS1. Recovery pain was excruciating for weeks. I coudln't walk or bend down to even change his nappy - DH was doing all the practical stuff for at least 3 weeks (he had planned a long time off work luckily)
Things still felt "taut" for yes, about 6 months after at least. We didn't have sex during that time - I didn't want to be put off the whole experience so wanted to make sure things were definitely ok down there. But to be honest, even then, at times sex was quite painful on erm, entry and um, until we'd er, got into it a bit ( and ) (smear not too bad though). There was no way I could have used tampons though - know exactly where you're coming from with the throbbing feeling. Not at all nice.
Still managed to conceive DS2 though, and had a brilliant normal birth with him although with a slight tear that needed a couple of stitches. Recovery time from that was totally different - just a teeny bit of pain for a couple of days (more a smarting really than any throbbing as I had with DS1). All fully back to normal within a fortnight. And I'm pleased to say that sex since then is now back to normal - ie. never feels tender, tight or painful at any time! Is that TMI again?! [blush}
An obstetrician stitched me up the first time, and looknig back, I am convinced she dit it too tight. It didn't feel really right until after I gave birth to DS2 and was stitched up by a midwife to be honest. Whether it's down to the skills of whoever stitches you up or whether it's simply that I had a lot more and deeper stitches after the ventouse I'll never know.
But I am very pleased with how it feels now (although it will never LOOK the same as it did before childbirth LOL!)
Hope that gives you some hope if you are despairing that things will never be right again, as I thought for a long time after DS1.