Because your ego feels the need to be satisfied & you are willing to look outside of your marriage to have your ego satisfied rather than working with your wife on healing the wounds & scars & working on strengthening your marriage relationship. It's the easy way to get your ego satisfied without having to do any work on healing your marriage.

So you have scars.......a lot were because of your drinking in the first place......& a lot of the wounds were because neither your wife nor you were able to communicate in a mature, responsible way that would make your marriage grow together rather than apart......so now you are looking at the rubble that caused & still not willing to work at making your marriage a REAL RELATIONSHIP (which in reality, it never was). It's as much your wife's responsibility as it is yours to grow your marriage into a real relationship......but real relationships aren't about the sparks that you felt before. When a marriage starts off, that's lust, NOT LOVE.....but it's what draws 2 people together who are attracted to each other.......the real marriage relationship has a lot more mature aspects to it than sparks.....it has working for common goals, just caring & being there for each other along with RESPONSIBLE BEHAVIOR on each person's part along with being able to take over for the other person when or if the need arises in a very responsible manor.

You are not wrong in wanting to feel wanted & needed nor is it wrong for you to not want to feel beat down......but you are wrong in looking for the solution outside of your marriage.....the solution needs to come from both you & your wife working on this problem because it's a red flag that there's something wrong in the marriage that NEEDS TO BE FIXED.....& I'm sure there are many things that your wife know needs fixed also if you both were able to be honest with each other.......a really GOOD marriage counselor would really be what your marriage needs now.....not some girl outside of your marriage making you feel good about yourself.

I left my husband & I can honestly say, I HAVE NOT & WILL NOT look for some guy to make me feel good about myself......I am able to feel quite good about myself without it coming from some guy. Feeling good about yourself NEEDS TO COME FROM WITHIN.

So that's where I'm coming from.

I really hope for your kids sake that you & your wife will be able to work through the wounds & the scars & give your kids the stable home that they deserve. IMO, it doesn't surprise me that your daughter is having problems given the truly unstable marriage that you both have that your children are existing under.