Savannah,I too have had difficulty similar to yours throughout my life with family members,those claiming to be christians and those denying Christ.I have some thoughts i hope will help.
Sometimes we will consciously come into what I recognize within myself as ' an intellectual ' agreement with the concept of practicing forgiveness versus being able to receiving the 'heartfelt' forgiveness that is part of the "all things pertaining to godliness" belonging to you that God promises us through His Word. I know you're longing for that elusive heartfelt peace providing forgiveness in the situation you describe. You sound broken hearted and confused by the relationship and your sincerity is obvious. Irregardless of the commonplace jokes surrounding mothers-in-law I believe every wife desires to be loved by her beloved husband's mother, in fact , it probably feels like something of a betrayal to find you are not, and it is normal to feel a sense of grief for the reality of the loss of what 'should be'. You may also be angry that you are being robbed of what could or in your mind should be a fulfilling and loving relationship.Grief is painful, loss is painful.Pain hurts and since we can only stand so much hurt we begin to build walls around our hearts to protect ourselves from the pain and disappointments life hands us. We also begin to choose to be angry instead of feel that helpless sense of pain,anger is mistaken for control,helplessness is a sense of lack of control,so we will often feel the pain and then immediately grab for anger because it makes us feel more in control less powerless over the pain. This is a typical natural man reaction to emotional trauma or abuse.You may even understand intellectually why she seems to thrive on such negative attention, yet still be wounded emotionally , and continuously, so that it seems you barely get a sense of equanimity before the attack starts again.This can be like going through surgery requiring stitches only to have someone come along and rip open your wound again.
An intellectual acknowledgement of your 'christian duty' to forgive will only go so far in these scenarios. There are ways you can better cover the specifics in this situation to illicit a more thorough release from the pain which is causing you fear,( the uneasiness you mentioned) and the uptight (angry)frustration which btw is an offspring of impatience.Define your root causes and be better equipped for battling this one through to victory.We need to remember to ask for what we need, in this case divine love to overcome. God's love and forgiveness for her flowing through you, yours won't cut it. Also familiarize yourself with key concepts that will uphold you during times of exposure to the individual in question,we must understand what we already have so we can claim this when in doubt. For example,we ask for the forgiveness for this person from God,and we receive the ability to forgive our entire spirit ,soul (our will,emotions and our mind) and body will be united in the receiving of God's love which provides generously to all who ask in faith. Initially when we do not feel the forgiveness yet,we must live by faith not feelings,but peace is a feeling ,is it not? Compassion is something Jesus felt?Ask for spiritual eyes to see her,love her,respond to her the way the Father sees her,loves her ,would respond to her with divine unbiased compassion. In order to turn this around your motive must be purified ask God to do this for you.Why do we forgive,to be forgiven? Selfish motive,this is one reason some never receive real forgiveness for others. Allowing God to build His protective walls of rooted and grounded love and faith as a shield around your heart so that the years of struggle can lose their sting the wounds can be cleansed and healed and a newness of God's powerful work being in progress.be in an expectation of God to move,to teach you how to love this quarrelsome individual.I can speak from experience,practicing forgiveness like this is so rewarding so awesome when everything shifts. Also I found checking your own heart for self pity is mandatory.
Understanding what your expectations are will help you in learning how to love this frustratingly hard-to-love family member. In Psalms David says 'My expectation shall be in my God.' One of my favorites as it instantly reminds me no one will always meet my expectations no matter how valid my complaint. If I am expecting anyone to treat me lovingly or with respect , to keep their word,etc,I will be severely disappointed,It always seems God Himself is blocking me getting my needs met this way,no matter who I'm expecting to meet my (valid or imagined) needs. Instead I am pleasantly surprised when others behavior affects me positively.I do not expect others to fail me either,it is simply a shift in focus which frees me to love them better. When you begin to get this one down , it opens a place in your spirit where it is harder to disappoint me because you did not live up to my expectations.If you are feeling frustrated confess your impatience,this clears the way to thank god for his provision of the long-suffering (patience)He has already given you, as it being a fruit of the spirit,and thus is 'pertaining to godliness',so you have it whether you know it or not, give thanks that you can access any of this at any time.Believe for her salvation,stand in faith for her to be blessed by God to repent that she too could experience God as you do. I know you have felt all these things for her before at one time or another,Jesus gave you His gospel ,the good news that you can be forgiven and forgive,He will bind up your broken heart and give sight to where you are blind in this matter and set both captives free , you who are chained to all that has come before with this woman,(all things can become new) and her to her sin as well.
I apologize if this attempt at encouragement jumps around a bit, unfortunately I don't have the luxury of time for a better presentation of these thoughts I hope will help you. Oh and ignoring our emotional reactions to painful things is not wise,but we are not led by our emotions however paying attention to the way we tend to respond and what follows is how we learn needs to change as in the way we think and ultimately the way we 'feel'. You cannot deny something that is never acknowledged,bring it out into the light ,expose ot then deny it choose something godly to fill the space whee that other ungodly thought or 'feeling'held court. With practice we can be trained to pause and then choose how we will respond. Responsibility= the ability to respond vs reacting or re- enacting the same behavior over and over Re-act=act it out over and over,a behavior pattern that creates locked in ruts that we get stuck in.Remember,respond a choice,responsibility the ability to respond. When we take responsibility for our ungodly and /or emotionally ignorant reactions,calling them what they are we are able to confess them as the sin they are,we can be cleansed ,our motives purified and our success a given.We can and will love the unlovely in our close personal lives. Consider her a gift , a golden chariot to lift you to higher places in Christ, Uppermost in our hearts and minds O God,how can I love this person as You would,Please do this through me, Father ,inspire me to love more creatively show me the way!Yes we choose to forgive,make it real Lord!