Hi, I'd like to help you with your question.
I am sorry about your losses. That is a lot to deal with for anyone.
You mentioned trying to see a therapist with your husband. Now I am going to recommend you see a therapist by yourself. With the amount of loss you have suffered, you need the chance to talk out your feelings and to process your losses. Talk with your doctor about a referral. If you attend church, your pastor would be a good person to talk to. If you want, you can also search on line at http://therapists.psychologytoday.com/rms/. You need the support right now.
With so many losses, going through the grief process is inevitable. There are five stages of grief that you may go through- Denial, Anger, Bargaining, Depression and Acceptance. Some people go through some of the stages, some get stuck in one and others go through all of the stages. Regardless of your experience, being aware of your grief is the most important thing to do. If you are aware, then you can work through and help yourself heal.
Here is a good link to help you understand more about grief: http://www.helpguide.org/mental/grief_loss.htm
Through all of this, you may be experiencing many different feelings. Give yourself time to deal with them and don't forget to get as much support as possible. It is ok to vent. It is ok to be angry or hurt by your husband and tell your friends about it. True friends understand and allow you to express yourself without judging. Think about attending a support group or having all your friends over for a girls night. How about your family? If you have anyone to share the loss of your father with, it would be family that understands the most.
Take care of yourself as well. Some pampering to help your self esteem would go a long way. When you discovered your husband has already started a new relationship, you took a hit to your self esteem. Consider going out and having your hair done. Or your nails. Buy a new outfit. Or whatever makes you feel better. It will not fix the problem or gloss over the emotions, but it will help you remember that you are worthy of feeling good again, and soon.
Here are some books that may help you:
On Grief and Grieving: Finding the Meaning of Grief Through the Five Stages of Loss by Elisabeth Kubler-Ross and David Kessler
Rebuilding: When Your Relationship Ends, 3rd Edition (Rebuilding Books; For Divorce and Beyond) by Bruce Fisher
I hope this has helped you,