Hi Sally. I have committed adultery in the past and I too am dealing with guilt. The only way I have been able to deal with it is by talking to God, by truely repenting and asking his forgiveness.
I haven't committed adultery, but I can give you the advise that Jesus gave to the women caught in the act. Go and sin no more unless something worse happen to you.
Proverbs 28:1He that covereth his sins shall not prosper: but whoso confesseth and forsaketh them shall have mercy.
1 John 1:9 If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness.
Read Psalm 51, it is all about King David's repentance from adultery, and murder.
Some times the hardest thing to deal with is the consequences of adultery, such as a broken marriage, broken relationships, etc.
Sin is very deceitful and will try to get you to minimize it, to blame other, and say things like if my husband was--- then I would not have done it. The other man kept pressuring me, He listened to me when my husband wouldn't.
God said to Cain if you do the right thing then it will be well with you, but if you don't sin is at the door with all the consiquences.
God is faithful to forgive us and to cleance us from all sin.
There is now no reason to suffer from guilt now that you are forgiven.
Let your heat instead be filled with love and worship for how kind He has been to you.