Tara, the order of dominance in eyes is Brown, Blue, other colours. Everyone has 2 copies of every gene. Dominant genes show themselves, recessive genes hide away, they are masked by the dominant gene - rather like no-one noticing a quiet introvert behind a curtain in the corner of the room when there's a big noisy extrovert in the middle of it. Both are there, just one is hidden.

You clearly have a brown gene, but for your children to have another colour then you aren't homozygous (have both copies of the gene the same), but heterozygous (different copies).

Your DP would probably have homozygous blue.

Your parents would be heterozygotes too, this is shown by your brother having green eyes and not brown. There is a 1:2 chance of you inheriting a gene as you are half your mother and half your father... OK, this is going to get complex here.

Father has gene A and gene B (same gene, just different copies).
Mother has gene C and gene D (same gene as the father, just different again).

Child can have A or B from Dad AND C or D from Mum.
Child's genetics show one of the following: A and C; A and D; B and C; B and D. No A and B or C and D as you can't inherit two copies from one parent.
If both parents have A and B, the child can have A and A; A and B; B and A; B and B. Or, to put it simply, they have a 1:4 chance of AA, 1:2 chance of AB, 1:4 chance of BB.

Now, parents have genes for eye colour. B is brown eye colour and dominant, b is non-dominant. Both parents have B and b genes.

The children can therefore have B and B (1:4 chance), B and b (1:2 chance) or b and b (1:4 chance). Three children (BB and Bb) have brown eyes, one child (bb) does not.

I hope this made some sense.