I don't think there should be any comparison between Bill-Hillary vs Mona-Pradeep.
However since comparison is made I would say Hillary has every right to forgive Bill.
1. Bill didn't walk out of his marriage neither he filed divorce , he was always married to Hillary and accepted his mistake.He was never in love with Monika.
2. Pradeep not only wanted divorcem, he also said he only loves Anushka and she is his first love and will be.
3. Pradeep was living with Anu and always showed disrespect and kept on humiliating Mona for who she is.
4.Pradeep questioned Mona's value and doubted her being pregnant with Vineet as it clearly shows very narrow and old age mentality.
After all these scenarios I can't say that Mona can forgive his as Hillary does. Hillary might have political goal, but Mona doesn't have any such thing other than her kids and she can take care of them even if she is married to some other guy or being alone.
we are copmaring apple and orrange but I thought I better put my 2 cents.