If you are married and have fallen in love with another man and realised you are gay the only thing you can do is tell your wife and be prepared to end your marriage.
Painful I know, but if you are cheating on her you need to be honest with her and true to yourself. This situation cannot be good for any of you. I'm assuming here that you mean you are in a straight marriage at the moment, but either way, your current marriage partner deserves your honesty.

I would be more concerned that you are cheating on your spouse...

Gay, straight, or bi, doesn't matter. The point is, is that you have and are cheating. You need to be honest and tell your wife.

The situation does not have to be hopeless or dire.
Talk to your wife. Explain the situation. If you still do, explain the love you still have for her.

See if she is willing to try an open marriage. If she is not, be prepared to end it.
But at least ask. It can't hurt to ask her.

You should have talked to your wife BEFORE having sex with someone else--gay, bi, straight, I don't care. You're CHEATING.

Be prepared to be broke for a long time as you will probably be paying alimony and paying for your wife's counseling for messing with her head like this.

Better pray you didn't also bring home a disease to her.

Talk to your wife, but be prepared for your marriage to end.

I agree with Synnen. You're cheating.

I feel most sorry for your wife. Too bad you couldn't have realized all of this before you married her, led her to believe that she had a man that loved her.

It's time to tell the truth to her, be honest, accept the consequences for your actions against her, and go from there.

Cheating is cheating.

Do things the right way from this point forward. Stop having sex with your 'friend'. You shouldn't continue that relationship until you are out of your marriage and have healed from the whole mess.

Are there any children involved? If so, arrange for them to be out of the house for a long time while you talk to your spouse and get everything out on the table. Be prepared for a volcano to erupt. Be prepared to need to leave the house. Together explain to the children that there will be changes and answer questions as needed. Arrange for family counseling to keep the confusion, hurt and upset to a minimum.

If there aren't any children, pack your bags to be ready to leave the house. Tell your spouse the truth and face the consequences.

Understand that this will not be easy and there is going to be a lot of anger and hurt and things said that probably shouldn't be, but that is part of cleaning up the mess you have gotten yourself into.

Whatever you do DO NOT try to place the blame for your actions anywhere other than on yourself. You had choices and you made them. Take responsibility for them.