I have used the Feliway diffuser, plugged into the outlet in my center hall, when it first came on the market. Milo was, and really still is, a bit on the jumpy side, and I had hoped it would work, but I had really no success with it. It may have been that I only had one going - the cost was even worse when they first came out and it was wasn't providing enough to fill the whole house and he would almost have to be laying next to it to work. I gave it to my breeder, and she said it worked when she used it in one room where the "uptight" kitties would be, so it may be worth it to try one. I think the initial diffuser should work about a month and you will know by then if it is going to have an effect. Maybe the poor boy is picking up on the vibes from b/f?
Good luck. I know the smell is something awful. My guys don't spray, but I have had one in the past that would.
No Heaven can be Heaven if my cats are not there to welcome me
Yes, I believe in the Rainbow Bridge