I didn't understand a lot of it.
1: The ex-colleague of Watson, Watson asked him where he was living now (so he didn't know) but later Sherlock deduced that the nurse woman had seen the wedding invitation. How did he have an invitation if they didn't know where he lived?
2: Why did the photographer go on dates with the women who worked for the ex-soldier. What did he get from them?
- Sherlock said that all the women had a secret. What was their secret and how was it relevant?
- How did the photographer get the job as photographer.
I think there was more but that's all I can think of for now.
All in all, quite a disappointing episode. I liked drunk Sherlock and Watson, but as PPs have mentioned it was wrong for Sherlock to become self-aware regarding his social skills.