Divorce Source: Is It Really Over?

hello everyone. i've been married for 12 years but we've been together for 20. my wife kicked me out of our home back in may of this year for rambling through her stuff. i guess i should start from the beginning, huh. before we were married we had our share of ups and downs but we managed to weather those storms, i thought. well, about 5 months after we were married my wife started back seeing an old flame of hers. i found out and she moved out and got her own place for about 3 months. then she came to me wanting to work things out. she said that in order for our marriage to work, we needed to relocate. so we moved to nashville. after moving to nashville, i found out that she was still seeing and talking to this other fellow. finally, after about 2 1/2 years she ended the relationship. i forgave her and we moved on. but things just were not the same. there were serious trust issues. she ended up going back to college(evening classes) and received her degree in bs mgmt. she also had our daughter in all these activities, in which my daughter was not happy about, that took away from her being home. so by the time she would get home she was wore out. she would do her home work, go over our daughter's home work and then get ready for bed. she would complain about me watching tv at night because she says she can't sleep with the tv on. if i tried to make love to her, she would say not right now because she was tired or our daughter was not asleep or wait until the morning. of course, i would get an attitude because i felt that she was neglecting me and my needs. so, needless to say, i had an affair with a co-worker about a year and a half ago. she found out and tried to throw me out our home. i refused to leave because i had no where else to go. so, after a while, she decided that we were going to get through this and move on with our marriage. well at the beginning of this year, everything changed. she started saying that after our daughter graduated from high school, which was this past may, she was calling it quits. so from january until may things were just awful. we barely spoke to each other and when we did we argued. there was no sex nor did we sleep in the same bed. we basically were separated while living under the same roof. so one day while i was home alone i started going through her stuff looking for clues as to see if she was having an affair. i found some old diaries she kept and read all this stuff about how she wanted out of this marriage. so when i asked her about it she got upset and locked me out of the house because she took my keys a few months earlier while i was in the shower. i never asked for them back because i felt i shouldn't have to. well since then i've moved back to my hometown. i've tried to reach out to her to see if we can try to repair our marriage but she refuses to do so. she said that she doesn't want to go to marriage counseling or anything like that. about a month ago she text me and asked me to meet her to sign the divorce papers that she printed off on-line. i refused to do so. i told her that since we didn't have a $200 wedding why should we have a $200 divorce. my thing is should i continue to fight for my marriage or let it go? should i take her to court or just sign the papers she printed off the internet? our daughter is 18 so child support is not a factor. we do have a house and she also makes more annually than i do due to her being a college graduate. and since the separation, i've had to quit my job in nashville and get a job here in my hometown making less money. what do i do? i'm not going to lie, i love my wife and divorcing her is the last thing i want to do. help!!