Hi,
1. Oily lubricants can affect the chances of conception, yes!
2. Couples can explore various options to enhance their sexual drive, and watching porn might be one. But avoid anything that makes you feel uncomfortable.
3. Erection issues are common for men trying to conceive. The reasons are having to perform on specific days, partner demand, anxiety about pregnancy etc. Its important to rule out other causes as well.
Next Steps
consult a sex counselor near you. you would benefit from counseling and specific guidance.
Health Tips
Staying calm, practicing meditation, breathing exercises, and/or relaxation exercises helps a lot. You both should realize that anxiety might cause erection and lubrication problem and also delay conception. Just do what you should and leave the rest to take its own course.