If you have a judgment (order) against him mandating the payment of alimony, and he isn't paying it, then you will have to take him back to court to obtain a financial judgment against him and/or contempt sanctions. Sadly, this is all on you - no one is going to enforce your alimony order for you.
This answer is not to be considered a response to a specific legal issue in a specific jurisdiction - it is to be considered only a general response to a hypothetical scenario posed by the questioner. For specific legal advice, please consult with a licensed attorney in your jurisdiction.
If you have an award for spousal support there are a number of different ways that you can go about collecting it.
Whichever method you choose, it is wise to first paper your trail BEFORE trying to collect the spousal support. You may be able to collect without involving lawyers or the courts. You should start by sending your spouse an e-mail or letter stating that you haven't received the support due and you would like to know how they would propose paying (e.g., by check or deposit to joint account). Try to keep the tone civil and friendly, because anything you send in writing is subject to review by a judge.
If your spouse doesn't respond or pay, then you should consider next steps like a motion to enforce. Remember, you cannot use a motion for contempt for failure to pay money due to the Oregon constitution's debtor's rights section. Depending upon how your judgment was characterized, you may also be able to enforce the judgment by applying for a lien or garnishment, or by hiring an attorney to conduct a judgment debtor's examination.
Remember that any of the approaches in the paragraph above will themselves cost money, so you must engage in a costs-benefits analysis to determine if it makes sense to front the costs for these collection efforts. Remember, in Oregon it is unethical for an attorney to take a family law case on a contingency basis, and there is no guarantee that you will be able to ultimately collect from your spouse. As they say "You can't get blood from a stone."
Generally speaking I encourage you to try and settle this dispute in a friendly manner. I recommend against using scorched-earth tactics in family law cases whenever possible. This is especially true for cases where you and your spouse are co-parenting children.
This post is offered as general information and is not intended as legal advice. This information does not in of itself create any attorney-client relationship.