How important is attraction in marriage?

What if there was never any 'falling in love' or physical chemistry between you? What if your husband told you he was not, nor had ever been attracted to you. Was not nor ever had been in love with you? What if there was never any spark? What if you both felt that you had missed out on something having never 'fallen in love' or had with someone you were pionate about? What if you truly cared for eachother, didn't want to be alone, and had five children together whom you are devoted to, whose lifes you don't want to mess up? Is it totally selfish to go your separate ways, amicably, and look for that elusive something that may very well never be found?