Blending families: when his children are shared 50/50 and I am a sole parent. He may be feeling resentment toward my child because his can't always be around. Help!

Hey there!I'm a single mom in a long term relationship with a single dad. We're at the point in our relationship that we're considering what marriage and blending families would look like. He has his kiddos 50/50, and I have my kiddo all the time. They're similarly aged and get along very well. After considering it for a while, he mentioned in conversation that he feels uncomfortable with the idea of being around my child more than his own. However he is still really pushing wanting to get married and blend. His concern is legitimate, I understand that must be tough. It is relevant to mention that we would like to have another child in a few years. This would mean both the "hypothetical child" and mine living with us full time and his living with us part time.I understand that the discomfort comes from wanting his kids to always be with him. But at the same time, my number one job right now is to put my child's interests before my own. I'm afraid that his feelings could lead to resentment toward my child. My feeling is not unfounded, as he has expressed having a difficult time with the differences between his kids and mine. His are more quiet, rough and tumble, go outside and play. Mine is very talkative, expressive, and inquisitive. Our parenting styles vary in ways and are similar in other ways. For example I work in occupational therapy, my minor was in child and family studies, so child development and parenting makes sense to me. I am more patient yet hands on. He tends to be a little more old fashioned. I feel like we could balance each other. I'm wondering whether his feelings are more to do with the general differences of our kids or feelings of resentment.​He's a great person, I enjoy our time together, but I know that not only am I choosing a partner for myself but I'm choosing a step-parent for my child. Are his feelings to be expected? Or is this a red flag? Any help is appreciated.(FYI I suggested he see a therapist to help cope with his feelings associated with timesharing, and he's been seeing someone.)xposted to r/stepparents​ via /r/Parenting https://ift.tt/2MzY0Qk