OP - only you can decide if your DP is "doing enough" as a father, and if you feel that he isn't, then whether that is a deal breaker for you.
Different people place different value on "family commitment" and it depends whether you will lose respect for your DP if he continues to "keep the peace" in this way.
Maybe, what you need to find out is what else he could be doing and which of those things it's reasonable (in your opinion) to expect him to do. There are lots of resources on the internet, in libraries and even here in MN giving advice to non-resident parents whose contact with their child is limited. If, when reading them, you find yourself thinking that your DP should be doing these things, then you need to find out why he hasn't? Is he aware of the steps he can take to change things, but has chosen not to, or does he not know what he can do to try and change things? Is he happy with the way things are and wants it left alone, or is he willing to change things in order to secure a future with you?
You may decide, for instance, that in order to demonstrate his commitment to you, it's reasonable to expect him to engage in mediation with his ex. So he can propose a different arrangement for contact. You may also decide that if all his contact with his DCs is dependent on him spending time with his ex, then this isn't the relationship for you.
As long as you are clear about your own boundaries, rather then demand your DP changes what he chooses to do, then you aren't being unreasonable. It is totally within your own power to decide whether you are willing to compromise, and if so, what about - or whether you decide that your DHs choices are deal breakers.
I hope you work it out.