my partner has been very reckless with sex and often doesn’t use protection with their male partner and there have been a few occasions where they have thought they may be pregnant and there have been a few occasions they said they’d been trying and i always get upset because they never talk to me about this and i feel its something they should be discussing with other partners if they’re planning to have a child? am i overreacting?

No, you’re not over reacting. Your feelings are your feelings, and you get to have them. Someone else might not care about this. But you do. 

The first step is to talk to your partner about this. Tell them what makes you feel concerned: “If you’re planning to get pregnant, I feel like I should be included in the conversation about that decision. Can we talk about how this impacts me?” Hopefully that conversation goes well and you two can take a more collaborative position on this.

In the end, though, there’s a big difference between “I feel like this situation deeply involves me” and “You need my permission to get pregnant.” You don’t get to make that call for someone else, and if they say “Nope, I don’t want or need to take your input into consideration, I am going to get pregnant or not based on what I want,” that is their right.

Your right, at that point, is to decide that you don’t want to be in that kind of relationship or situation. You may decide that a relationship with this person isn’t working for you because of their current family planning situation and the way they communicate about it. That’s for you to decide.