Three questions:
1)Is it normal to see more ab definition when you're bulking even though there is more fat on your gut?
It is normal to have "some" ab definition as body fat increases (even above 10%, and factors related to starting point). However, at some point (logically) it will disappear.
2)Is it to be expected that your waist size will go up when bulking?
I think its safe to say that its a rather high probability the pant size will go up on a bulk. How much depends on the diet and training methods and the specific to individual person.
3)How do you guys deal mentally with the increased fat?
Personally, I do not deal with it well. Chillen with mental problems (okay, be quiet,

)
I have completed some intense personal programming just to get fat loss down to a personal science (during the 30+ pounds I lost, and then engineering a battle for the last few body fat percents down to 8%).
I just learned what makes me happy at this stage of my life at 46 years old, and it is fair to say, I don't want to engineer the battle for a bulk (I am capable believe me, my desire can set some pretty high standards and self appropriate restrictions, I would be a certified trainers dream),----but its a desire that does not set me on fire.
This isn't a vain statement: I get allot of personal satisfaction knowing I had put a lot of personal effort in what I accomplished, and every time I walk out the front door of my house, there is a high probability I look 50 times better then the next person near my age (and in some cases persons half my age) and in better health.
During a bulk (as you already know) the purpose is to put on some lean muscle mass. Some fat will accumulate and this is rather normal.
During a bulk you are setting up and preparing the framework to allow the leaning down (cutting period) to reveal your hard work of the bulk. You are preparing the "concrete that will set later".
This is the first step in a two step process; though there is a high probability of dealing with some small annoyances and processes within the first (bulk) and second (cut) steps. For some its not necessarily in this order (cut can be first, and bulk afterwards, dependent on the individual).
For some, one of these annoyances or processes are the mental acceptance of fat gain during a bulk. You already know you will gain fat tissue; however, it is still somewhat bothering you.
It's my opinion, a person has to seek out a counter measure for every conceivable weakness and have a plan of action to attack it. Is this feasible? I believe it is for those with a high motivation and desire to achieve. I don’t want to here it isn't practical (blah, blah), make it practical. So much time is given to training and dieting, and not so much time to the "very personal issues that can ruin and spoil it for a person". Expect personal battles and have a plan, and a plan of action for when new ones develop: Have this so engrained in the mind, that the one can react favorably when the need arises.
It always begins with the mind--before outward action can happen. The mind in fitness is grossly underestimated to the performance of a personal goal. The mind and body can "destroy" ones goals or make one a "warrior", and for most, its their choice which one happens.
I believe in: Seek and you shall Find. But, its more than applying simple definitions to SEEK and FIND.
In everything I read, I actively participate in "active learning". I seek relevant and irrelevant topics to my problem (or mental problem with diet and training) and spin off "active thought". I take the topic (or topics) and actively seek if there are variations and additions to the topic (or topics) that I can add (or modify) and molded it to me personally and assist my situation.
Take my post in the McDonald's Thread for example, some (its possible) may just see this as another Chillen post (oh, hum), but what they may not see is---what I do to make me tick and move my goal clock forward. Being narrow minded can be a very bad thing. And, one may get much from simple statements. I NEVER have bad motives on the forum.
Here is what I wrote in the event you didn’t see the post:
In this article, there are a few positive and important learning messages that stand out for those that are willing to see it and use it to a personal goal advantage. THIS ARTICLE ROCKS!
----->------>"Oooops", says an average deficit dieter, "I ate a 300c candy bar. OH! I'm still within my calorie restrictions; its all good. I don't have to fall off the deep end and get sad or depressed. I STILL ROCK!"
Reading with Correct Perception + Applying what can be Learned = Personal Goal Advantage
Deliberately and earnestly look for things that can help you on your goal path, PEOPLE! In everything you see! YES LEARN BABY. Learn to master yourself!
It can help in figuring out your "personal puzzle"
Yes.,.......figure this damn thing out, make it work! Live and learn all day everyday!
Are your eyes open? Do you truly see? Earnestly look for knowledge to BEAT DOWN adversity.
Your personal answer is there, Phil. Actively and persistently seek and apply "active learning" coupled with "active thought" and find the one that works for you. Once you apply something that you find that works for you, it will motivate you to look for more, and can build a brick house that will not fall when the wind blows.
This is my advice to you, my friend,
Best regards,
Chillen