Of course you have needs too, that's only normal. Incidentally, the feeling of not having your needs met or being able to properly progress in the relationship is one reason why many people don't like vees in practice (sometimes they work when al people are ready; sometimes they don't, and usually for the reasons you're stating). Being a secondary who isn't being treated well is never fun for anyone.
Would you consider dating other people as well as him, so you can get those needs met and keep things with him more casual (because essentially, these rules below will keep you two on a casual basis)? It is hard to know how long it will take for your boyfriend's wife to open up to the idea of a more egalitarian relationship. I wouldn't want to sit around waiting for my needs to be met either. Some people take many years before theyre emotionally prepared for that kind of relationship; some may never get there.
So I think you have several choices: leave and pursue someone who is able to treat you like an equal, provide you with consistency, or b) stay with him and yet pursue a relationship that can be more serious for you/more able to meet all your needs while your relationship with him goes rather slow. I'm sure there are other choices out there too that I don't know about
Best of luck!