If it turns out to be false, you would have damaged your relationship. If your spouse has been acting funny, in more serious cases, you may want to consider hiring a private detective to allay your worries. Maybe he or she really has been working late, not partying. The point is, take action to find out the truth. It could be a figment of your over active imagination.
Divorce is a nasty word, especially when there are kids involved.
If you do decide on this path, be prepared for a tough road ahead and steel yourself. The first thing you should do is get a lawyer you trust and feel comfortable working with. Discuss the options available to you with the lawyer. You ll likely feel some stress also, so reach out to your family and friends for support, or see a counselor. It helps to relieve any feelings of anger or sadness if you can talk it out with a qualified counselor.