Why did Chris's mom Barb treat Bob badly like dirt even though she wanted a stable husband exactly like bob to marry?

I don't understand why Chris's mom Barb treated Bob badly and neglected him, even though Bob was the one who kept the Chandler household together and made sure that the mortgage was taken care of, the debt was managed, and that barb and Chris were left with $40,000 and the SSDI tugboat to ensure they would be taken care of when Bob would eventually pass on. What wasn't Bob giving to Barb that Barb really needed?

Chris did say that Barb desperately wanted to be a wife to a stable, solid man. Yes I know Bob wasn't a perfect man as Bob was stubborn and had no backbone who needed to stand up and tell Chris to stop doing dumb things, but at least Bob tried to fix things and he did keep the house running as the credit card debt and family finances was decently managed when he was around.

According to what Chris himself said based on CWCKi entries, Chris and Cole said the majority of men that Barb dated in her life treated her badly and that Barb had a long history of men leaving her as seen with her 3 divorces. One marriage of which lasted for only 1 year. Another marriage, with Jack Smithey, which in Chris's word: "Short story of it is that Jack and Barbie went out, sexed up, knocked her up.Then he hit the road; was not in it to be a daddy. The life on the open road called out to him more."

So what I don't understand, is how Barb saw a guy like Bob, a stable, solid, Army veteran who just got divorced and willing to do anything to make her happy, and Barb said to herself "wow, this Bob guy looks like the safe and stable type of man I've always wanted to marry and be a spouse to...I'm going to treat this guy like dirt, throw a temper tantrum when he asked me to clean up the hoard, tell at him when he tells me to stop spooning my adult son, and let him die alone covered in bug bites."

I can't understand why Barb treated her ex husbands Jerry and Jack smithey like royalty and talk positive about them while putting her ex husbands on a pedestal, but then treat bob like an unwanted toy in the clearance bin?

Why would Barb say shed wanted a stable/healthy person to date and marry, BUT then when she gets what she wants (Bob) she neglects him and then they complains to her son Chris about how people are shit...why this happen?