I am jealous of my husband's ex-wife?

Hi, I am 28 year old widow with no children who has recently gotten remarried. My new husband has also been married before and has three little boys by his ex-wife. The problem is that at times I feel jealous of her. We currently live in the house that my husband and his ex-wife bought together. She left two months after they moved in because they could not agree on finances.Some of her things pictures, home movies, letters ect.. are still in the home. I don't believe he knows that they are still in the house. I am jealous because she is the mother of his children. Although we do not have any chidlren now we do plan to have chidlren of our own in the furture. The fact that she finished school and I just started, she has his children, they bought this house together are all reason why I sometimes get jealous. Get this she doesn't even know that we are currently married. Also from what I heared I don't think she is over their reationship. I think that if she could make different decisons she would not have left the marriage. We had a very quick courtship before we got married and that I did not really have a chance to digest all that I was getting myself into. Although, I married a wonderful man and I know he loves me dearly. Even with all that I am thinking about desloving our marriage because I don't think I can handel this situation for much longer.