Answer:

When Adam and Eve fell from grace and received the consequences of their sin, God told Eve, "I will greatly multiply your sorrow and your conception; in pain you shall bring forth children; your desire shall be for your husband, and he shall rule over you" (Genesis 3:16). On some level, we all understand that men and women approach life from different viewpoints, but often we neglect to think about the impact of these differences in our dealings with one another. God designed women to be the center of the family. Her outlook is emotionally based. Seemingly minor things in one aspect of life strongly affect her view of other aspects of life.

When God said that a woman's desire would be for her husband, He is stating that a woman looks to her husband for stability in her life. You gave a blow to the stability of her world when you left your job. You didn't mention how long you remained unemployed, but since you mentioned that you drifted apart, I am guessing that it wasn't a short time. Most women don't feel sexy when life is uncertain, especially when sex is likely to result in yet another mouth to feed.

Men approach life differently. Again going back to the fall, God told Adam, "Cursed is the ground for your sake; in toil you shall eat of it all the days of your life. Both thorns and thistles it shall bring forth for you, and you shall eat the herb of the field. In the sweat of your face you shall eat bread till you return to the ground, for out of it you were taken; for dust you are, and to dust you shall return" (Genesis 3:17-19). Men define themselves by their ability to provide. Though you did not mention the reason why you left your employment, I suspect that it was reluctantly and not because you had immediate better prospects. You also damaged your outlook on life and sought to "prove" that you were still manly by sex. Yet, all it proved was that you were stronger. To your wife, it declared that you were uncaring of her feelings. Recall Peter's words, "Husbands, likewise, dwell with them with understanding, giving honor to the wife, as to the weaker vessel, and as being heirs together of the grace of life, that your prayers may not be hindered" (I Peter 3:7). Instead of seeking to understand the cause of your wife's lack of desire, you focused on proving your worth to yourself. Instead of honoring your wife, you degraded her; you treated her as a prostitute instead of a companion.

This began a sequence of events that caused your marriage to spiral out of control. Perhaps in vengeance and a desire to be wanted by a man, your wife sought comfort from another man. Into this already shattered relationship now comes a wedge of mistrust. The one ray of hope is that she is willing to stay with you; that tells me she believes the marriage is salvageable, even if she is not actively working toward a solution.

Like most things, building takes much longer than destruction. It will take many months, if not years to restore your relationship back to the level it was once at. I'll try to map out some things for you to work on, but realize that I'm working at a disadvantage. I only know what you have told me and I don't know your wife's viewpoint. Since you are the one asking, I can give you suggestions, but I can't offer suggestions for your wife since she isn't asking. I still recommend counseling for yourself, even if your wife is unwilling to go. Having multiple views on a problem will minimize the number of mistakes that you might make.

1. Restore stability in your life. If you haven't done so already, find a good stable job. Make sure your finances are in good shape -- no one wants to be living hand-to-mouth. Work on budgets together and plan where you would like to be in one year, five years, and ten years. Nip future problems quickly before they cause damage. "Catch us the foxes, the little foxes that spoil the vines, for our vines have tender grapes" (Song of Solomon 2:15).
2. Treat her with honor. The past cannot be changed, but you can change the future. Stop trying to fix the past; instead, work on building a future. Act as if you are back in the days when you dated your wife. Shower her with random acts of kindness. Show you care by asking her how her day has gone and then sit down and carefully listen to her. "O my dove, in the clefts of the rock, in the secret places of the cliff, let me see your face, let me hear your voice; for your voice is sweet, and your face is lovely" (Song of Solomon 2:14).
3. Restore trust. Trust often takes time to build, but there is one element that you can work on immediately. You stated that there is a child on the way, but you are not certain if you are the father. My question for you is: "Does it matter?" You are already "daddy" to two little girls who didn't develop from your sperm. Does the lack of genetics make you any less a father? Because they are not blood-related, do you love them any less? In most states, it doesn't matter who the sperm donor is; the man married to the woman is automatically the father of the child. Take the plunge to restore trust in your marriage. Your wife says the child is yours. Take her at her word. Show that you trust her by no longer expressing doubt or asking for a test. Fully accept the child as your own because you are the only dad that child will ever need.

All of this might not work. Despite your best efforts, your wife still has free choice, and might chose to undermine all that you do. But right and wrong doesn't depend on you wife's acceptance. Do the best that you can, knowing that it will give you the best possibility of settling the problems.