Some questions that may help...
Are you ready to risk spending the rest of your life alone in order to keep seeking true love?
Are you generally happy in your relationship, or are you pushing yourself to feel that way? Apart from chemistry, what is you don't like? What else is missing?
Keep in mind that passion fades by the years, and also a soulmate isn't necessarily your male clone.

I thought both of my exes were true loves...the one was deep passion-but we had different life goals and ideals. The other was exactly the reverse. And there was that one guy I felt he was my true soulmate, but I pushed him away because I'd have to double-time at that point. After all that I realized I can't be truly happy with someone who is half of what I need. But lonely life is very hard, and I know I may never find anyone, ever...so it's a personal decision.