Should she stay or go?

Ok, so I'm having a hard time giving my cousin advice on her situation. Her and her hubby have been married for 17 years, I think. Anyway they live close to his family but very far away from her family. They have been in a trailer on their land for 6 years atleast and it is very cramped with them and the 3 kids. It only has 2 bedrooms and her oldest son is in 8th grade now and he doesn't even have a bedroom. He sleeps on the couch. Her husband said he'd get started building the house this summer, it never happened with the way the economy is. There's always an excuse from him, he's self employed and he says he has either too much work so no time or too little work and no money. He wants to build a house without going full on into alot of debt so, wont get a bank loan. He's not real motivated to build with this economy now though. They have lived in this cramped single trailer for atleast 7 years. She works at a job she loves but it's at a private school so, she has summers off. Not the best pay but, good benefits for her and him since he has none because he's self employed. She'd have a hard time with money if she left and would want to move closer to her family thus she'd lose her job which does have like a pension type retirement plan she wouldn't want to loose. She's getting close to 40, sick of her home life, and doesn't know what to do. She always stayed because she loved him but, now she's not sure she does anymore. She says she just realized that she doesn't feel like she loves him anymore, never wants to have sex with him and hasn't for a couple months, not attracted to him in that way anymore. She doesn't hate him but isn't sure she loves him. She's also overweight and I think she think's she can't find someone new.

Anyone ever felt this way or wasn't sure???

She loves him because of he's her kids father but, not lust like love. I guess they live like roommates. She feels trapped because she knows money-wise her kids would suffer without the support of him being there and having a roof over their head. He's also self employed so child support, forget it he can say he doesn't make enough money. She also feels that if she left and hubby found someone else that that woman would benefit because maybe he'd actually build said house to impress someone new. She wouldn't be able to qualify to build with her income. She has even told him just to buy a bigger trailer with enough bedrooms, he won't, he wants to build his house. He's unmotivated to do so though. He could get a real job he once made alot of money but, wanted to try the self employed route because of less stress and now he likes that he has no boss so, he'll never go back I guess, even if it means the'd actually have more money. He has mentioned to her to get another job though, why doesn't he? I do not know how to help her or what to say. I feel so bad but, since I'm not in her shoes I don't know what to tell her. Has anyone ever had this experience or know what to say?