Ok everything your wife said I had heard from my W at some point or another.
The fact she doesn't find you attractive is pretty much a dead ringer here.
What have you done to make yourself more attractive?
Superficial stuff like getting in shape matters.
Now comes the biggest part:
I can tell by your actions that your W has very little respect for you. She knows that you will do ANYTHING to keep her by your side. (I mean you offered to raise another man's child!)
So she has very little respect for you. She's proven that time and time again. I am of the belief that if there is no respect, there is no attraction period. She probably does a thousand little things that test your ability to stand up for yourself and you probably fail them on a daily basis.
Does she seem like the type that nothing is ever done right, no matter how hard you try?
Is she the type that never knows what she wants when you go out, and none of your suggestions appease her?
Does she go into the biggest rage because things around the house are never done just the way she wants them?
Is she the type that cannot keep even simple promises like picking up the kids or getting something you ask for on the way home.
Do you feel like no matter what you do to make her happy it just seems to make her more and more upset and demanding in the long run?
If you answered yes to a lot of these questions, then her lack of attraction to you my friend stems from a lack of respect for you.
I like repeating this quote that a very wise woman told me when things were at their worse for me.
"I want a man that can stand up to me, because he can stand up for me"
It's a powerful statement because it taps into a very primal way of being and thinking for women. Strong is attractive, weak is not.
Right now any man or woman that has the guts to hit on a married woman is way more attractive than you.
She has you in her purse, waiting to receive a morsel of love. She doesn't have to be nice to you.
These OM/OW's she has to seduce them and win them over and prove to herself that she is worth something.
Now what can you do?
It's the little things my friend.
Is she always late? Start demanding she is on time.
Does she yell at you? Tell her you will not tolerate getting yelled at and will talk once she calms down.
Yells at you for not doing a chore right. Tell her that you are doing your best, and that this is acceptable to you, if she gets mad at that tell her that you are more than willing to do the dishes, but if it's such a big deal maybe she should do them.
Most importantly when she threatens to walk out, open the door.
If done right though you will notice that standing up for the little things will in time reduce how much big strife you see in your M.
I recommend you look up how to become an Alpha male and incorporate into your 180's. Imho There's a guy named Athol Kay that gives good advice on how to become a strong man while building a good marriage. Keep following DR, and sorry to say this bud but you're not piecing.
Just remember stand up for the little things and work your way up. The more you do it, the better it'll feel. She'll also respect you more and challenge you less.