My feelings are valid.

Valid means the feeling is real and has a cause. Jealousy is genuine information: it tells you precisely what you want and haven't admitted to wanting. It is rarely trustworthy about the person it happens to be aimed at.

Both things hold at once — the feeling counts, and it doesn't get to file the final report. Most people go wrong at one end or the other, either dismissing what they feel entirely or acting on it as though it were a verdict. Listen closely to it as evidence about yourself; hold it loosely as evidence about anyone else.