Just wanted to post my experience in the hope that it might help someone else.
Late 30s and unexplained infertility. No BFP in 2 years. After 2 years we were so sick of sex to order and I was so sore that I got my husband to ejaculate into a pot and I inserted it with a syringe, inserted as far as a could. BAM, 1st BFP that month. Sadly I miscarried but I did this 4 months on the trot and got pregnant every time with the 4th time ending up with my DD. Exactly the same happened with my son 18 months later. My fertility doctor was a bit perplexed but said that it might have deposited the sperm nearer where they needed to go. Maybe worth a try, particularly on the nights where you can't face DTD xx