The love a mother has for her son/daughter is different and asymmetrical from the love a son/daughter has for their mother. Especially when the people involved are all adults. The bond changes. It’s healthy. Some mothers have a hard time understanding that. Mine included, unfortunately.
The jealousy a mother may feel for her son/daughter’s spouse can be understandable, but it’s misguided. It’s extremely probable that a mother wouldn’t mean everything to her son/daughter even if her son/daughter weren’t married to anyone.