Sewing help for seams coming apart. Help!

Check your tension, maybe putting too much tension on the fabric. also, how old is the fabric itself? Can you tear it by hand easily? maybe its old, and can't take the mechanized sewing, i.e. the forwarding foot, or again, thread tension.

Sew a stabilising seam of straight stitches on edge of fabric then zig-zag row then again a straight row. Don't over stuff the cushion. Might be idea to add

a braid or piping or gusset to cushion covers.

Chenille is a soft open weave. With any pressure, it will pull open.

Use a lighter and lightly burn the seams. Dont burn the house down...

Thanks everyone! I'll give it another try

My fav trick for fraying fabric is to bind the seams with a bias tape, fold almost in half and stitch it along the seam you have already stitched, and then along the other edge covering the seam allowance. If the cushion has a curved corner, you going to have to stretch it a bit so it has some give.

I agree on sewing the two straight seams to help strengthen the area you are zigzagging. That should help some, just be careful filling it as was said, don't over stuff and occasionally check the seams to make sure they are staying together and you can catch it before it becomes too large.