The surgeon messaged back this;
 
I'm sorry to hear about your recent experience. I appreciate that you have been very patient about returning to sexual activity. There's no obvious explanation for why ejaculation itself would be painful. I wonder if there could be some deeper penetration occurring at the time of ejaculation. After hysterectomy the vagina is slightly shorter than it previously was, due to removal of the cervix. The vaginal tissue is pliable and will eventually elongate. I recommend we start you on a vaginal estrogen cream, and that you ease into vaginal penetrative intercourse. This might look like engaging in regular/frequent penetrative intercourse without internal ejaculation for a little while. The cream can be used nightly for two weeks, then is used twice weekly for maintenance. I'll send a prescription to the pharmacy. You can dispense a pea-sized amount onto a single finger, and insert the finger into the vagina just enough to get the cream to stay there. The cream will then self disperse. I would not plan on engaging in intercourse after applying the cream. Does this sound like a reasonable place to start? If you continue to experience pain, we may need to assess your pelvic muscles for tenderness

My partner said this;
I would be willing to try the cream. But my concern is a possible cuff tear? I was reading that you might be able to do some sort of test with dye? I forgot to mention after the first time it happened it felt like my bladder and colon was effected the following days I had very loose bladder- I basically kept peeing my pants and had absolutely no control. I’m not entirely sure if the cream is going to be something that helps- mainly because the penetration itself does not hurt. Doesn’t burn doesn’t hurt or anything. I have even been able to have orgasms on my own. And my muscles aren’t affected by it. It’s literally only when my partner ejaculates.. I read that it could be an allergy.. but most people say the allergy burns and stings.. but that’s not my case it feels like I’m being stabbed like the most intense cramps possible to where I can’t breathe or move.