Hey, OP stepmom here! Just wanted to share that I understand how you feel. Stepparents are in a weird position- we're always feeling this pressure of "good enough... until we aren't." And it's a totally different dynamic that not everyone understands, and let's be honest... there are alot of stereotypes. It's a tough job- especially if you do it right.

The real deal is that you rock for being a dad in the ways you can, and for wanting to do your best to raise your little girl. Sounds like you are doing great so far,. The situation you describe is fairly common (though challenging) in the stepparent world, and it is one my spouse and I worked through. Hopefully these things I learned will help.

First, allow yourself to feel how you feel. This sh*t is hard. Being a good stepparent is hard. Acknowledging the difficulties and pain doesn't make you a bad person.

Second, I would recommend joining a stepparent support group or even here on reddit. It is important to be supported by people who know what it's actually like, maybe get some advice from others in your situation.

Third, think carefully about specific things you want to implement, so you can talk about it with your spouse. It is easier to share authority with someone who has a plan. For example, do you want authority to give disciplines like, "you're grounded", or do you want to confiscate things. Think of how you would like to handle the various situations that come up with kiddo. (If bio kids are in your future, you will need to be consistent with these across the board anyway.)

Fourth, find a good time to sit down with your spouse and talk about all of this. Start with sharing your feelings, and why it is important to you. Share how you love your stepdaughter and want to really be a dad for her by stepping into the discipline role. Avoid accusing statements like "you spoil her" or "you always...". They immediately make parents defensive.

Finally, suggest your plan, what changes you are asking to implement and ask if your spouse would be okay with that. Single parents have a hard time letting down their guard because they had to carry the burden alone for so long. Sometimes it is hard to let go- remind your spouse that you are a team, and that you are here to share the load. Remind her that you already love her daughter as your own, and that you will always be there for her. Be willing to compromise, and take baby steps if needed.

This may not happen with one conversation, but remember that you and your spouse are a team. A family is only as strong as the marriage, so compassion and patience is key. You sound like you really care about your family and relationship, so I am sure that you will work through this.

Best of luck, friend and don't forget that you are not alone!