It is not a coincidence NO way. He's either too gut less to tell you whats really going on ....or he's stalling. Stalling to see what direction he and his wife need to go before burning the bridge with you ....stalling in hopes his wife will start missing her bf and resume relations with him which will green light things with you again. Stalling hoping you will push the issue or get fed up and break up with him first. There's a reason and you need to ask what it is. Lets see if I'm even close.
In his relationship who pushed to open things up...Her or Him??? Was this their first relationships after opening up ?
How did this guy come to live with them?