I don't agree with my ex-husband's parenting choices. Is there anything I can do?

You can file a divorce petition and establish custody. Until there's a court order for custody, both parents have equal legal custody rights in their children. Once a case is filed, a specific award must be made. There are two related issues to child custody: legal custody, and physical custody.
Legal custody refers to decision-making authority over a child. A parent with legal custody decides where a child goes to school and what religion they observe, makes medical decisions for the child, and so on. Parents can agree to joint legal custody, sharing this authority, but a court will not order joint custody unless the parents agree to it.
Physical custody, or parenting time, refers to where a child lives. Each custody case ends with a parenting plan describing where the child or children stay. These plans can be as specific or general as the parents need. The parents are free to deviate from the plan if they agree to do so, but the plan is there for when they can't agree. The harder it is for two parents to agree on these issues, the more important it is that the plan be clear and specific.
Usually, a parent who has legal custody of a child also has more parenting time, but this is not required. Parents can share equal parenting time while one has legal custody; or parents can share joint legal custody while one of them has physical custody most of the time.
Under Oregon law, decisions about legal and physical custody are made according to the best interests of the children. Obviously that's quite vague. But the law sets forth a few standards for determining the best interests of the children:
One principle is that the children should remain with the parent who spent most time with them before -- the "primary custodial parent." In this case, it sounds like you both have equal claims here. The law also presumes that it is in the best interests of the children to have an ongoing relationship and continuing contact with both of their parents. If the court must decide which parent is awarded primary legal and physical custody, it is more likely to grant it to the parent who has shown that they will encourage an ongoing relationship between the children and the other parent. Parents should not try to keep their children away from each other, unless one parent has clearly been abusing the children.
Oregon law explicitly does not consider the lifestyle choices of each parent in child custody decisions, except as it affects the welfare of the children. Judges do not want to hear parents attacking each other in court; the focus is on the children, not on each person's faults. That said, a parent's refusal to work with the other parent, or to mind the children's safety from things like cigarette smoke, will not look good to a court.
Another common means to figure out the best interests of children in a custody case is to order a professional custody evaluation. In this process, a social worker will interview the parents and the children, observe them interacting with each other, maybe visit both parents' homes, and make a recommendation to the Court. Judges follow these recommendations almost all the time. The problem is that these evaluations can be fairly expensive: $1,200 for court-appointed evaluators; $3,000 or more for a private evaluation, which is rather more thorough. Parents are typically asked to pay equally for these costs, or to pay in proportion to their incomes.
You should consult with an attorney if you're going through a divorce. You can call the Oregon State Bar for a free referral at 503-684-3763.

I don't agree 100% with my esteemed colleagues. But they are on the right track. They are both right that you need to move forward and get a divorce going before your concerns will be heard. While it is true that this could lead the courts to designating a primary parent and a parenting plan and that this does mean the primary parent has more say in certain day to day decisions about the children, it does not mean that the courts specifically use the terms "legal" custody versus "Physical" custody. It is helpful to break it down like that to explain the concept but these are not terms that the court generally uses. The bottom line is that absent a mutual agreement for joint custody and shared decision making - which I don't think is going to work given your situation - there will need to be a way to pick a primary parent where the children reside most of the time and the other parent will have the children coming over to stay with them on the days they get pursuant to the parenting plan. In terms of cigarette smoke it is a known health hazard and you you have every right to ask for restrictions that keep your children from being exposes. I think I judge will grant you that request. As for the computer you also have good reason to be concerned and there are plenty of applications that can be installed to restrict the access children have to things like pornography that a request for limits like this would probably be met favorably by the court. But in terms of what the children do when they are at dad's house - it is really up to dad to set how he wants to do his parenting time during his time. So if he wants to play video games for hours with the children that's his choice. If the children have health issues and need more physical activity per their doctors recommendation then maybe some limits would be in order and dad may be required by the court to plan some physical activities as part of the daily routine. So it is going to be up to dad subject to limits that you ask the court to impose if there is a real health or safety issue that merits the court restricting dad's rights. I would start looking for an attorney and discuss these issues with them. It might also be wise to plan a strategy to insure that you end up being the primary parent. Be advised that the Lawyer Referral service Mr. Bodzin suggests is only a list that attorneys pay to be on. They tell the office what types of cases they want. When you call you get the next person on the list. There isn't any special screening or matching going on. The attorney will have to pay the Bar Association a percentage of the fees they collect from you. This service tends to attract less experienced attorneys that are just starting to build their practice. The one advantage of this program is that the attorney must promise to speak to you for $35. You will find that the more experienced attorneys don't participate in this program. You might as well use the internet or pick some names off of Avvo and start calling around. http://www.portlandlegalservices.com