My life was better before my fiancée

UPDATE: She and I spoke - which ended up with us not speaking for a few days. She apologized for how she was treating me and promised things would change; it's a week later and I've started trying to change my life around, and she has already reverted back to her old behaviors. I'm tired of feeling this way. I know what I should do, but I don't know how. I can't afford a deposit for an apartment anymore, let alone the actual rent, and I don't have anywhere else to go. My family loves her and I'm scared to disappoint them if I leave.

As the title says - my life was better before I was with my fiancee.

My fiancée and I have been together for several years at this point; we got engaged a few months ago and have started planning our wedding. I love her, I really do but lately I can't stop thinking about how much better my life was before being with her.

Before her: ● I lived in a nice, comfortable apartment. ● I went to the gym every morning. ● I was in the process of losing weight, and lost over 100 pounds. ● Not only was I saving money but I was also paying off debts ahead of schedule.

Now: ● She wanted to move in together but she couldn't afford the rent at my previous place as we would have had to up-size bevause she has a son and we would have needed another bedroom; so I moved into her home, which is run down and falling apart. ● I can't even remember the last time I've been to the gym- I prefer to go in the mornings as there are less people and it works better for my work schedule; however, whenever I try to go in the morning she guilts me for leaving her in bed alone and I'll hear about it for the rest of the day. ● Not only can I not go to the gym without being guilted every time - but if I try to eat healthy meals (which she won't do) then I'm guilted for eating a different meal than her; that I'm "too good" to eat with her. I've been gaining the weight back as I end up giving in because I don't want to listen to her complain. I'm disgusted to look at myself now - she wants to leave the lights on when we are intimate but seeing myself in the light completely kills the mood for me and lately I haven't wanted to be intimate because of it. ● I make more money than her, especially since nearly half of her income goes to her child support for her son - and I could comfortably afford to go do things before we were together, but now of course she wants to do everything too and she can't afford it so I end up footing the bill. I have a hard time telling her no and my credit cards keep getting more and more put on them because I can't afford it for the both of us. Especially when it comes to her son - somehow I'm the one who ends up paying for everything. We have him one week on and one week off, and yet I'm the one buying groceries for when he's here, I'm the one buying his birthday and Christmas presents, I'm the one planning his birthday parties, I'm the one paying for everything.

Overall, I know I'm too blame for my own actions; I know I'm the one who moved here, I know I'm the one not going to the gym, I know I'm the one eating poorly, and I know I'm the one spending the money, but I'm beginning to resent her for putting me in these situations.

We're planning our wedding, looking at different catering companies, and yet, in the back of mind, I'm starting to resent her.

And I resent myself for it.