@Gift
Pole sana,your pain and confusion is evident through your words,but take heart,there's more to life than an unappreciative partner and though infidelity is considered a solid ground for divorce,is it the best and only option? Will you and your kids be happy staying away from the father?
My lame advice..
First of all,that day you spotted the panty,is the day you should have RUN!Did you put a name & face to the panty btw?ama that story just died after the lame apology? That same panty owner could be the constant ghost that your hubby has been cheating with! An old affair

Lakini since you didnt RUN then,and maji sasa yamemwagika..lets focus on the present situation.
One thing our elder women don’t make clear to us,is that a man will at some point be tempted to, or cheat on you. And trust me,it has nothing to do with you being good or bad in bed. Men are easily turned on, and alarmingly turned off at an even greater pace! so no matter how many kungwi sessions you attend,you might be
missing the point elsewhere in your marriage.
Do you satisfy him emotionally? Do you treat him as if your world still revolves solely around him,ama after the kid you started putting in lots of effort on your daughter and forgot you had another kid before her(your hubby)? Men need undivided & selfless love and attention from their wifeys no matter how old or young they are!He could be acting out
Secondly,The wife might have bedroom moves but has she maintained her shapely body?one might buy a killer lingerie,but if all your hubby sees are stretchmarks and flab around all the wrong areas,yet he knows of this dead gorgeous girl in his office,or he passes by Applebees sometimes..then you better match up with your killer moves with a more attractive you, there might be something tempting him to go after his fantasy girl, without intending to hurt you at all by the way.
Do you have a flowing,interesting converstaion with him,ama after the marriage all conversations became an inquiry,request or complain?e.g Kuja na diaper... or utakunywa chai?.. or kwani huwezi kuwa home mapema for once?
Anyhow, DON’T give up on your marriage, Your kids need both parents and moving out wont solve anything. The same way he wooed you with apologies all those times he has cheated on you,he will probably woe you back. Talk about this to an older couple, or some understanding relatives from either side,and have an informal sit in with them to let him know how it deeply hurts you, and that how terrified you are of the consequences of his action which would affect you, his unborn child and even break your young, beautiful family. If this fails,see a professional shrink,maybe your hubby has a problem and needs help like Tiger Woods
And above all, Pray a lot

. Let God be your friend and guiding star. He never lets his faithful servants down. Pray and believe. And of course, focus on positive things in life,keep yourself busy, Focus on being a great yet humble wife and through the grace of God,your hubby will soon see the Precious,dream wife in you. DON’T GIVE UP and don’t let your emotions lead you.
Nevermind what haters say, ignore them til they fade away - Just live your life