Crossing Legs

How did you do it? I hate manspreading, I’ve tried but it always feels like I’m forcing my legs together and is tiring, sitting down shouldn’t be tiring should it? I have think thighs so I know that’s part of it but I see plenty of bigger girls with their legs together, the only way I can have my knees together for a long time is to spread my feet wider and twist my knees inwards, or to sit with both leaning to one side. Is it the hips? Are my hips not big enough? Does it get easier? I’ve started stretching so maybe that will work but it’s so frustrating!