There have been issues with depression in the past. And when it was, it was treated with counseling and therapy as well as a variety of different medications. The meds worked but made the desire for sex even less which increased the problems and fighting. The meds caused bigger issues for her such as excessive sweating, insomnia, and lack of a back bone meaning that she went with the flow of life with no emotions and everyday was a blur.
So she quit with the meds and he threatened to leave her if she didn't get back on them. She couldn't win for losing. There are other issues involved as well. He is a hard working man and a good provider. However, he provides no help at home with child, chores, regular maintenance of owning a house, etc. she works too. She stays frustrated at his lack of interest in his role at home and constant concern of just sex. He doesn't take care of his hygiene like he did when the relationship first started such as brushing teeth regularly (that's a big thing). Even with this, she IS attracted to him but doesn't know how to approach it. Also, there are lots of underlying issues with his family. On multiple occasions he has allowed his family to treat her poorly and has refused to stand up to them on her or their child's behalf, right or wrong. And with time the relationship has turned into simply coexisting for their child's sake. Her heart is still there though, or she would have left for good instead of always coming back. He doesn't see where he does wrong, he just feels like he is being done wrong. She has no desire to be with him or any man for that matter. He isn't concerned with fixing any problem but the lack of sex. He had not stepped out that she is aware. With him working like he does, he doesn't have time. And he is home when he is suppose to be. He doesn't go out.