At the age of 50 people, may not want to look beyond their current life style, beliefs and comfort zone. Anandi is 40 in the show and kamli is also around 23-24. This indicates that Mangala is around 50, and if she had a child back then, her child would be married too and may be had kids. Mangala would be a grand mom by now.
So at the age of 50, a person will not have sudden "desires". Taking liberty like dressing in colourful clothes or merry making during celebrations, is different from feeling attracted to another man.
Even Anandi danced in Jagya's wedding or dressed up in Diwali for Nimboli's sake. So is it fair to conclude that she is also feeling attracted towards another man? She also had to suppress her "desires" post her loving husband's death, and it has already been 12 years, so does that mean she should remarry?
Wanting to see Mangala getting married at the age of 50, (considering her beliefs and ways of living) is like suggesting a partner for Dsa or Meenu (at their age before leap). Even the open minded ones like Meenu or Dsa had difficulties in going overboard with celebrations / attention, what makes people think that Mangala will go all the way to get married?
Mangala has no such desires, plus the time has passed.
Mangala found a new hope in Nimboli while she was leading an aimless life. She loved her, cared for her and yes she doesn't want to lose her. She is clingy and her methods of retaining Nimboli are wrong, but she is certainly not looking for a man.
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In all honesty, Anant has been introduced for Anandi and he is smitten by her. Even if Anants to remarry, he will need someone to suit his taste. For now, Anandi fits the bill in every way. Their age, compatibility, education, style of thinking, living, culture, society etc matches. Anant hardly shares any commonness with Mangala.
So obviously it's not Anant and Mangala.