How long do you wait for better sex?

My husband and I haven't  had decent sex since our first year together. The past three years have been bad due to stress with work and constant travel etc. We are in a pattern of hardly doing it. He now believes we are in a position to start focusing on making it better. Truth is He is on the smaller side and I miss having sex with a larger man both in body and penis size. As well as a man who has a hunger for sex as in making me feel desired because he has to have it. I never have that dominated feel with him.  Its nice that he wants to improve it and there are things we can do but I feel hopeless about it. If it doesn't get better I'm not sure I can live the rest of my life with this kind of a sex life. How much more time should I allow to pass by if its not working?