I know how you feel, trust me I do. My wife came out as Poly a couple of years ago. We'd been together for 5 years before that, and when she told me she wanted to start seeing this other man she was interested, I was devastated. I won't lie to you; I hurt, I cried, I was depressed, I raged, I rode a roller coaster of emotions and the peaks were a lot smaller than the valleys. I alternated between wanting to leave her and fear of her leaving me. I never thought it would work out and I would end up alone.
It didn't work out that way at all. I told my wife how I was feeling, I made sure she knew how it made me felt. We talked, so many times, long into the night, we argued, we discussed like rational adults, we talked until our brains hurt. In short, we communicated honestly and openly about everything we were feeling. Things got easier over time. My fear of being left for 'the other man' slowly went away and although I still had (and have) jealousies and the niggling fear that any babies in our relationship may not be mine, things got easier. We negotiated some ground rules. You have a right to feel the way you feel, but you need to talk to your wife about how you are feeling. If you trust her, and she has told you that you are her life and her love, then believe her. I'm not saying there's no way she'll ever leave, hell, my wife might decide to leave tomorrow, but she's being honest with you and with herself and that's a very good sign.
I would suggest to you that you really work on figuring out how you feel, and why you feel the way you do. I would also suggest that you tell your wife when you do figure it out, and talk to her as often as you can about how you feel and what you want. Relationships are always a lot of work, and compromise is the name of the game if a relationship is going to last. You are making a compromise in sharing your wife on an emotional level, it's only fair that she be willing to make compromises for you. What works for me may not work for you, but trust me when I say that honesty and open communication is always the best policy in these situations. No doubt the road will be rough at times, but it's up to you to decide whether that road is worth it. I don't know a darned thing about you, but believe me when I say you are worth it and you are worthy of being loved, everyone deserves love.
Another thing you can do is really work on loving yourself. It's hard since our society sees self-congratulation as a conceited, but it's healthy to have self-respect and self-worth. It makes a man more attractive than a flashy car or muscles of expensive clothing, and many women have told me that. Be honest with yourself about your achievements, feel proud of the accomplishments you've made, try not to compare yourself to others. Last of all, don't believe that a poly relationship is some kind of 'unnatural' way of going through life. It's been reinforced in society that monogamy is the norm, and statistically it is, but there were times when slavery was the norm, when beating your wife was accepted and even encouraged, and look where we are now. Our society views monogamy as the norm, but that doesn't mean it's the only way to go through life and it doesn't mean it's normal. I hope you got something out of this and I have helped in some small way. You are not alone.
-Love is all you need
