i agree with wolf, a marriage should have a stronger bond than a unmarried couple. They made a vow!
Tasha1133,
you heart will tell you if it's worth it or not, but also use common sense in the situation.
Remember in a relationship, two people could feel entirely different. for example when i was happy in love with my ex boyfriend, he was miserable for a long time and didnt tell me.
Did you find out why he cheated? was it someone showing him interest, making him feel good about himself, strongly perusing him, or did he pursue because he didnt feel appreciated by you, did he feel miserable at the time, confused about what he wanted.etc.....